diff --git a/app/models/form_handler.rb b/app/models/form_handler.rb
index 4ba300552..13df48af4 100644
--- a/app/models/form_handler.rb
+++ b/app/models/form_handler.rb
@@ -79,12 +79,12 @@ class FormHandler
 
   def lettings_in_crossover_period?(now: Time.zone.now)
     forms = lettings_forms.values
-    forms.count { |form| form.start_date < now && now < form.end_date } > 1
+    forms.count { |form| form.start_date <= now && now < form.end_date } > 1
   end
 
   def sales_in_crossover_period?(now: Time.zone.now)
     forms = sales_forms.values
-    forms.count { |form| form.start_date < now && now < form.end_date } > 1
+    forms.count { |form| form.start_date <= now && now < form.end_date } > 1
   end
 
   def use_fake_forms!
diff --git a/app/models/validations/date_validations.rb b/app/models/validations/date_validations.rb
index 1884560b7..299146c44 100644
--- a/app/models/validations/date_validations.rb
+++ b/app/models/validations/date_validations.rb
@@ -68,6 +68,37 @@ module Validations::DateValidations
 
 private
 
+  def active_collection_start_date
+    if FormHandler.instance.lettings_in_crossover_period?
+      previous_collection_start_date
+    else
+      current_collection_start_date
+    end
+  end
+
+  def validation_error_message
+    current_end_year_long = current_collection_end_date.strftime("#{current_collection_end_date.day.ordinalize} %B %Y")
+
+    if FormHandler.instance.lettings_in_crossover_period?
+      I18n.t(
+        "validations.setup.startdate.previous_and_current_financial_year",
+        previous_start_year_short: previous_collection_start_date.strftime("%y"),
+        previous_end_year_short: previous_collection_end_date.strftime("%y"),
+        previous_start_year_long: previous_collection_start_date.strftime("#{previous_collection_start_date.day.ordinalize} %B %Y"),
+        current_end_year_short: current_collection_end_date.strftime("%y"),
+        current_end_year_long:,
+        )
+    else
+      I18n.t(
+        "validations.setup.startdate.current_financial_year",
+        current_start_year_short: current_collection_start_date.strftime("%y"),
+        current_end_year_short: current_collection_end_date.strftime("%y"),
+        current_start_year_long: current_collection_start_date.strftime("#{current_collection_start_date.day.ordinalize} %B %Y"),
+        current_end_year_long:,
+        )
+    end
+  end
+
   def previous_collection_start_suffix
     previous_collection_start_date.year % 100
   end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 77c3bd997..5e55fb16f 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -136,9 +136,6 @@ en:
       above_min: "%{field} must be at least %{min}"
     date:
       invalid_date: "Enter a date in the correct format, for example 31 1 2022"
-      outside_collection_window:
-        crossover_period: "Enter a date within the %{previous_collection} or %{current_collection} financial years, which is between 1st April %{previous_collection_start_year} and 31st March %{current_collection_end_year}"
-        not_crossover_period: "Enter a date within the %{current_collection} financial year, which is between 1st April %{current_collection_start_year} and 31st March %{current_collection_end_year}"
     postcode: "Enter a postcode in the correct format, for example AA1 1AA"
     location_admin_district: "Select a local authority"
     email:
@@ -158,6 +155,10 @@ en:
           "Enter a date within the %{previous_start_year_short}/%{previous_end_year_short} or %{previous_end_year_short}/%{current_end_year_short} financial years, which is between %{previous_start_year_long} and %{current_end_year_long}"
 
       startdate:
+        current_financial_year:
+          Enter a date within the %{current_start_year_short}/%{current_end_year_short} financial year, which is between %{current_start_year_long} and %{current_end_year_long}
+        previous_and_current_financial_year:
+          "Enter a date within the %{previous_start_year_short}/%{previous_end_year_short} or %{previous_end_year_short}/%{current_end_year_short} financial years, which is between %{previous_start_year_long} and %{current_end_year_long}"
         later_than_14_days_after: "The tenancy start date must not be later than 14 days from today’s date"
         before_scheme_end_date: "The tenancy start date must be before the end date for this supported housing scheme"
         after_void_date: "Enter a tenancy start date that is after the void date"
diff --git a/spec/models/validations/date_validations_spec.rb b/spec/models/validations/date_validations_spec.rb
index f6b4fc1bf..07f10b25b 100644
--- a/spec/models/validations/date_validations_spec.rb
+++ b/spec/models/validations/date_validations_spec.rb
@@ -19,13 +19,13 @@ RSpec.describe Validations::DateValidations do
         it "cannot be before the first collection window start date" do
           record.startdate = Time.zone.local(2021, 1, 1)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 21/22 or 22/23 financial years, which is between 1st April 2021 and 31st March 2023")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 21/22 or 22/23 financial years, which is between 1st April 2021 and 1st July 2023")
         end
 
         it "cannot be after the second collection window end date" do
           record.startdate = Time.zone.local(2023, 7, 1, 6)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 21/22 or 22/23 financial years, which is between 1st April 2021 and 31st March 2023")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 21/22 or 22/23 financial years, which is between 1st April 2021 and 1st July 2023")
         end
       end
 
@@ -38,13 +38,13 @@ RSpec.describe Validations::DateValidations do
         it "cannot be before the first collection window start date" do
           record.startdate = Time.zone.local(2022, 1, 1)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 financial year, which is between 1st April 2022 and 31st March 2023")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 financial year, which is between 1st April 2022 and 1st July 2023")
         end
 
         it "cannot be after the second collection window end date" do
           record.startdate = Time.zone.local(2023, 7, 1, 6)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 financial year, which is between 1st April 2022 and 31st March 2023")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 financial year, which is between 1st April 2022 and 1st July 2023")
         end
       end
     end
@@ -59,13 +59,13 @@ RSpec.describe Validations::DateValidations do
         it "cannot be before the first collection window start date" do
           record.startdate = Time.zone.local(2022, 1, 1)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 or 23/24 financial years, which is between 1st April 2022 and 31st March 2024")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 or 23/24 financial years, which is between 1st April 2022 and 9th July 2024")
         end
 
         it "cannot be after the second collection window end date" do
           record.startdate = Time.zone.local(2024, 7, 1, 6)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 or 23/24 financial years, which is between 1st April 2022 and 31st March 2024")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 22/23 or 23/24 financial years, which is between 1st April 2022 and 9th July 2024")
         end
       end
 
@@ -78,13 +78,13 @@ RSpec.describe Validations::DateValidations do
         it "cannot be before the first collection window start date" do
           record.startdate = Time.zone.local(2023, 1, 1)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 23/24 financial year, which is between 1st April 2023 and 31st March 2024")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 23/24 financial year, which is between 1st April 2023 and 9th July 2024")
         end
 
         it "cannot be after the second collection window end date" do
           record.startdate = Time.zone.local(2024, 7, 1, 6)
           date_validator.validate_startdate(record)
-          expect(record.errors["startdate"]).to include(match "Enter a date within the 23/24 financial year, which is between 1st April 2023 and 31st March 2024")
+          expect(record.errors["startdate"]).to include(match "Enter a date within the 23/24 financial year, which is between 1st April 2023 and 9th July 2024")
         end
       end
     end