diff --git a/app/services/bulk_upload/lettings/year2024/row_parser.rb b/app/services/bulk_upload/lettings/year2024/row_parser.rb
index 3d34d6305..3f5227c44 100644
--- a/app/services/bulk_upload/lettings/year2024/row_parser.rb
+++ b/app/services/bulk_upload/lettings/year2024/row_parser.rb
@@ -617,7 +617,9 @@ private
   def validate_address_option_found
     if log.uprn.nil? && field_16.blank? && key_address_fields_provided?
       error_message = if log.address_options_present? && log.address_options.size > 1
-                        I18n.t("#{ERROR_BASE_KEY}.address.not_determined")
+                        I18n.t("#{ERROR_BASE_KEY}.address.not_determined.multiple")
+                      elsif log.address_options_present?
+                        I18n.t("#{ERROR_BASE_KEY}.address.not_determined.one")
                       else
                         I18n.t("#{ERROR_BASE_KEY}.address.not_found")
                       end
diff --git a/app/services/bulk_upload/sales/year2024/row_parser.rb b/app/services/bulk_upload/sales/year2024/row_parser.rb
index b28581edb..443d5e665 100644
--- a/app/services/bulk_upload/sales/year2024/row_parser.rb
+++ b/app/services/bulk_upload/sales/year2024/row_parser.rb
@@ -615,7 +615,9 @@ private
   def validate_address_option_found
     if log.uprn.nil? && field_22.blank? && key_address_fields_provided?
       error_message = if log.address_options_present? && log.address_options.size > 1
-                        I18n.t("#{ERROR_BASE_KEY}.address.not_determined")
+                        I18n.t("#{ERROR_BASE_KEY}.address.not_determined.multiple")
+                      elsif log.address_options_present?
+                        I18n.t("#{ERROR_BASE_KEY}.address.not_determined.one")
                       else
                         I18n.t("#{ERROR_BASE_KEY}.address.not_found")
                       end
diff --git a/config/locales/validations/lettings/2024/bulk_upload.en.yml b/config/locales/validations/lettings/2024/bulk_upload.en.yml
index 892cd6f88..a22f65fa5 100644
--- a/config/locales/validations/lettings/2024/bulk_upload.en.yml
+++ b/config/locales/validations/lettings/2024/bulk_upload.en.yml
@@ -49,8 +49,10 @@ en:
           age:
             invalid: "Age of person %{person_num} must be a number or the letter R"
           address:
-            not_found: "We could not find this address. Check the address data in your CSV file is correct and complete, or find the correct address using the CORE site."
-            not_determined: "There are multiple matches for this address. Check the address data in your CSV file is correct and complete, or select the correct address using the CORE site."
+            not_found: "We could not find this address. Check the address data in your CSV file is correct and complete, or find the correct address in the service."
+            not_determined:
+              one: "There is a possible match for this address which doesn't look right. Check the address data in your CSV file is correct and complete, or confirm the address in the service."
+              multiple: "There are multiple matches for this address. Check the address data in your CSV file is correct and complete, or select the correct address in the service."
             not_answered: "Enter either the UPRN or the full address."
           nationality:
             invalid: "Select a valid nationality."
diff --git a/config/locales/validations/sales/2024/bulk_upload.en.yml b/config/locales/validations/sales/2024/bulk_upload.en.yml
index 860eae137..31daa09f7 100644
--- a/config/locales/validations/sales/2024/bulk_upload.en.yml
+++ b/config/locales/validations/sales/2024/bulk_upload.en.yml
@@ -39,8 +39,10 @@ en:
           age2:
             buyer_cannot_be_over_16_and_child: "Buyer 2's age cannot be 16 or over if their working situation is child under 16."
           address:
-            not_found: "We could not find this address. Check the address data in your CSV file is correct and complete, or find the correct address using the CORE site."
-            not_determined: "There are multiple matches for this address. Check the address data in your CSV file is correct and complete, or select the correct address using the CORE site."
+            not_found: "We could not find this address. Check the address data in your CSV file is correct and complete, or find the correct address in the service."
+            not_determined:
+              one: "There is a possible match for this address which doesn't look right. Check the address data in your CSV file is correct and complete, or confirm the address in the service."
+              multiple: "There are multiple matches for this address. Check the address data in your CSV file is correct and complete, or select the correct address in the service."
             not_answered: "Enter either the UPRN or the full address."
           nationality:
             invalid: "Select a valid nationality."
diff --git a/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb b/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb
index 01529a80b..14a1d9326 100644
--- a/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb
+++ b/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb
@@ -1710,7 +1710,7 @@ RSpec.describe BulkUpload::Lettings::Year2024::RowParser do
               end
             end
 
-            context "when no address has a high enough match rating" do
+            context "when a single address with not a high enough match rating is returned" do
               before do
                 stub_request(:get, /api\.os\.uk\/search\/places\/v1\/find/)
                   .to_return(status: 200, body: { results: [{ DPA: { MATCH: 0.6, BUILDING_NAME: "", POST_TOWN: "", POSTCODE: "AA1 1AA", UPRN: "1" } }] }.to_json, headers: {})
@@ -1720,7 +1720,31 @@ RSpec.describe BulkUpload::Lettings::Year2024::RowParser do
                 parser.valid?
                 expect(parser.errors[:field_16]).to be_empty
                 %i[field_17 field_18 field_19 field_20 field_21 field_22].each do |field|
-                  expect(parser.errors[field]).to eql([I18n.t("validations.lettings.2024.bulk_upload.address.not_determined")])
+                  expect(parser.errors[field]).to eql([I18n.t("validations.lettings.2024.bulk_upload.address.not_determined.one")])
+                end
+              end
+            end
+
+            context "when no addresses have a high enough match rating" do
+              before do
+                stub_request(:get, /api\.os\.uk\/search\/places\/v1\/find/)
+                  .to_return(
+                    status: 200,
+                    body: {
+                      results: [
+                        { DPA: { MATCH: 0.6, BUILDING_NAME: "", POST_TOWN: "", POSTCODE: "AA1 1AA", UPRN: "1" } },
+                        { DPA: { MATCH: 0.8, BUILDING_NAME: "", POST_TOWN: "", POSTCODE: "BB2 2BB", UPRN: "2" } },
+                      ]
+                    }.to_json,
+                    headers: {},
+                    )
+              end
+
+              it "adds address not found errors to address fields only" do
+                parser.valid?
+                expect(parser.errors[:field_16]).to be_empty
+                %i[field_17 field_18 field_19 field_20 field_21 field_22].each do |field|
+                  expect(parser.errors[field]).to eql([I18n.t("validations.lettings.2024.bulk_upload.address.not_determined.multiple")])
                 end
               end
             end
diff --git a/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb b/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb
index f3f7da486..0c38034db 100644
--- a/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb
+++ b/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb
@@ -1104,7 +1104,7 @@ RSpec.describe BulkUpload::Sales::Year2024::RowParser do
               parser.valid?
               expect(parser.errors[:field_22]).to be_empty
               %i[field_23 field_24 field_25 field_26 field_27 field_28].each do |field|
-                expect(parser.errors[field]).to eql([I18n.t("validations.sales.2024.bulk_upload.address.not_found")])
+                expect(parser.errors[field]).to eql([I18n.t("validations.sales.2024.bulk_upload.address.not_determined.one")])
               end
             end
           end
@@ -1128,7 +1128,7 @@ RSpec.describe BulkUpload::Sales::Year2024::RowParser do
               parser.valid?
               expect(parser.errors[:field_22]).to be_empty
               %i[field_23 field_24 field_25 field_26 field_27 field_28].each do |field|
-                expect(parser.errors[field]).to eql([I18n.t("validations.sales.2024.bulk_upload.address.not_determined")])
+                expect(parser.errors[field]).to eql([I18n.t("validations.sales.2024.bulk_upload.address.not_determined.multiple")])
               end
             end
           end