diff --git a/app/services/exports/lettings_log_export_service.rb b/app/services/exports/lettings_log_export_service.rb
index 404b9f0e6..e63219f7d 100644
--- a/app/services/exports/lettings_log_export_service.rb
+++ b/app/services/exports/lettings_log_export_service.rb
@@ -12,9 +12,9 @@ module Exports
       start_time = Time.zone.now
       daily_run_number = get_daily_run_number
       archives_for_manifest = {}
-      base_number = LogsExport.where(empty_export: false).maximum(:base_number) || 1
       recent_export = LogsExport.order("started_at").last
       collection_years_to_export(collection_year).each do |collection|
+        base_number = LogsExport.where(empty_export: false, collection:).maximum(:base_number) || 1
         export = build_export_run(collection, start_time, base_number, full_update)
         archives = write_export_archive(export, collection, start_time, recent_export, full_update)
 
diff --git a/spec/services/exports/lettings_log_export_service_spec.rb b/spec/services/exports/lettings_log_export_service_spec.rb
index 4e76364c4..65a41df26 100644
--- a/spec/services/exports/lettings_log_export_service_spec.rb
+++ b/spec/services/exports/lettings_log_export_service_spec.rb
@@ -256,6 +256,32 @@ RSpec.describe Exports::LettingsLogExportService do
 
           export_service.export_xml_lettings_logs(collection_year: 2022)
         end
+
+        context "and previous full exports are different for previous years" do
+          let(:expected_zip_filename) { "core_2021_2022_apr_mar_f0007_inc0004.zip" }
+          let(:expected_zip_filename2) { "core_2022_2023_apr_mar_f0001_inc0001.zip" }
+
+          before do
+            LogsExport.new(started_at: Time.zone.yesterday, base_number: 7, increment_number: 3, collection: 2021).save!
+          end
+
+          it "generates multiple ZIP export files with different base numbers in the filenames" do
+            expect(storage_service).to receive(:write_file).with(expected_zip_filename, any_args)
+            expect(storage_service).to receive(:write_file).with(expected_zip_filename2, any_args)
+            expect(Rails.logger).to receive(:info).with("Building export run for 2021")
+            expect(Rails.logger).to receive(:info).with("Creating core_2021_2022_apr_mar_f0007_inc0004 - 1 logs")
+            expect(Rails.logger).to receive(:info).with("Added core_2021_2022_apr_mar_f0007_inc0004_pt001.xml")
+            expect(Rails.logger).to receive(:info).with("Writing core_2021_2022_apr_mar_f0007_inc0004.zip")
+            expect(Rails.logger).to receive(:info).with("Building export run for 2022")
+            expect(Rails.logger).to receive(:info).with("Creating core_2022_2023_apr_mar_f0001_inc0001 - 1 logs")
+            expect(Rails.logger).to receive(:info).with("Added core_2022_2023_apr_mar_f0001_inc0001_pt001.xml")
+            expect(Rails.logger).to receive(:info).with("Writing core_2022_2023_apr_mar_f0001_inc0001.zip")
+            expect(Rails.logger).to receive(:info).with("Building export run for 2023")
+            expect(Rails.logger).to receive(:info).with("Creating core_2023_2024_apr_mar_f0001_inc0001 - 0 logs")
+
+            export_service.export_xml_lettings_logs
+          end
+        end
       end
     end