diff --git a/spec/models/form/sales/questions/person_known_spec.rb b/spec/models/form/sales/questions/person_known_spec.rb
index 2635b939d..551ac096e 100644
--- a/spec/models/form/sales/questions/person_known_spec.rb
+++ b/spec/models/form/sales/questions/person_known_spec.rb
@@ -8,6 +8,10 @@ RSpec.describe Form::Sales::Questions::PersonKnown, type: :model do
   let(:page) { instance_double(Form::Page) }
   let(:person_index) { 2 }
 
+  before do
+    allow(page).to receive(:id).and_return("person_1_known")
+  end
+
   it "has correct page" do
     expect(question.page).to eq(page)
   end
@@ -27,44 +31,291 @@ RSpec.describe Form::Sales::Questions::PersonKnown, type: :model do
     })
   end
 
-  it "has correct conditional for" do
-    expect(question.conditional_for).to eq(nil)
-  end
-
   it "has the correct hint" do
     expect(question.hint_text).to eq("")
   end
 
-  context "with person 1" do
-    let(:question_id) { "details_known_1" }
-    let(:person_index) { 1 }
+  context "with a non joint purchase" do
+    context "and person 1" do
+      let(:question_id) { "details_known_1" }
+      let(:person_index) { 2 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_1_known")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_1")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 1?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 1?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_1" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(2)
+      end
+    end
+
+    context "and person 2" do
+      let(:question_id) { "details_known_2" }
+      let(:person_index) { 3 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_2_known")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_2")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 2?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 2?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_2" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(3)
+      end
+    end
+
+    context "and person 3" do
+      let(:question_id) { "details_known_3" }
+      let(:person_index) { 4 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_3_known")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_3")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 3?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 3?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_3" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(4)
+      end
+    end
+
+    context "and person 4" do
+      let(:question_id) { "details_known_4" }
+      let(:person_index) { 5 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_4_known")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_4")
+      end
 
-    it "has the correct id" do
-      expect(question.id).to eq("details_known_1")
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 4?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 4?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_4" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(5)
+      end
     end
+  end
+
+  context "with a joint purchase" do
+    context "and person 1" do
+      let(:question_id) { "details_known_1" }
+      let(:person_index) { 3 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_1_known_joint_purchase")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_1")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 1?")
+      end
 
-    it "has the correct header" do
-      expect(question.header).to eq("Do you know the details for person 1?")
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 1?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_1" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(3)
+      end
     end
 
-    it "has the correct check_answer_label" do
-      expect(question.check_answer_label).to eq("Details known for person 1?")
+    context "and person 2" do
+      let(:question_id) { "details_known_2" }
+      let(:person_index) { 4 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_2_known_joint_purchase")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_2")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 2?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 2?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_2" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(4)
+      end
     end
 
-    it "has the correct hidden_in_check_answers" do
-      expect(question.hidden_in_check_answers).to eq(
-        {
-          "depends_on" => [
-            {
-              "details_known_1" => 1,
-            },
-          ],
-        },
-      )
+    context "and person 3" do
+      let(:question_id) { "details_known_3" }
+      let(:person_index) { 5 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_3_known_joint_purchase")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_3")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 3?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 3?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_3" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(5)
+      end
     end
 
-    it "has the correct check_answers_card_number" do
-      expect(question.check_answers_card_number).to eq(3)
+    context "and person 4" do
+      let(:question_id) { "details_known_4" }
+      let(:person_index) { 6 }
+
+      before do
+        allow(page).to receive(:id).and_return("person_4_known_joint_purchase")
+      end
+
+      it "has the correct id" do
+        expect(question.id).to eq("details_known_4")
+      end
+
+      it "has the correct header" do
+        expect(question.header).to eq("Do you know the details for person 4?")
+      end
+
+      it "has the correct check_answer_label" do
+        expect(question.check_answer_label).to eq("Details known for person 4?")
+      end
+
+      it "has correct conditional for" do
+        expect(question.conditional_for).to be_nil
+      end
+
+      it "has the correct hidden_in_check_answers" do
+        expect(question.hidden_in_check_answers).to eq(
+          "depends_on" => [{ "details_known_4" => 1 }],
+        )
+      end
+
+      it "has the correct check_answers_card_number" do
+        expect(question.check_answers_card_number).to eq(6)
+      end
     end
   end
 end