diff --git a/app/services/imports/case_logs_import_service.rb b/app/services/imports/case_logs_import_service.rb
index adec47526..8eb272d62 100644
--- a/app/services/imports/case_logs_import_service.rb
+++ b/app/services/imports/case_logs_import_service.rb
@@ -96,8 +96,8 @@ module Imports
 
       attributes["prevten"] = unsafe_string_as_integer(xml_doc, "Q11")
       attributes["prevloc"] = string_or_nil(xml_doc, "Q12aONS")
-      attributes["previous_postcode_known"] = previous_postcode_known(xml_doc)
       attributes["ppostcode_full"] = compose_postcode(xml_doc, "PPOSTC1", "PPOSTC2")
+      attributes["previous_postcode_known"] = previous_postcode_known(xml_doc, attributes["ppostcode_full"])
       attributes["layear"] = unsafe_string_as_integer(xml_doc, "Q12c")
       attributes["waityear"] = unsafe_string_as_integer(xml_doc, "Q12d")
       attributes["homeless"] = unsafe_string_as_integer(xml_doc, "Q13")
@@ -142,15 +142,17 @@ module Imports
       attributes["postcode_known"] = attributes["postcode_full"].nil? ? 0 : 1
 
       # Not specific to our form but required for consistency (present in import)
-      attributes["old_form_id"] = Integer(field_value(xml_doc, "xmlns", "FORM"))
+      attributes["old_form_id"] = safe_string_as_integer(xml_doc, "FORM")
       attributes["created_at"] = Time.zone.parse(field_value(xml_doc, "meta", "created-date"))
       attributes["updated_at"] = Time.zone.parse(field_value(xml_doc, "meta", "modified-date"))
+      attributes["old_id"] = field_value(xml_doc, "meta", "document-id")
 
       # Required for our form invalidated questions (not present in import)
       attributes["previous_la_known"] = 1 # Defaulting to Yes (Required)
       attributes["la_known"] = 1 # Defaulting to Yes (Required)
       attributes["is_la_inferred"] = false # Always keep the given LA
       attributes["first_time_property_let_as_social_housing"] = first_time_let(attributes["rsnvac"])
+      attributes["declaration"] = 1
 
       unless attributes["brent"].nil? &&
           attributes["scharge"].nil? &&
@@ -163,8 +165,19 @@ module Imports
       end
 
       case_log = CaseLog.new(attributes)
-      case_log.save!
+      save_case_log(case_log, attributes)
       compute_differences(case_log, attributes)
+      check_status_completed(case_log)
+    end
+
+    def save_case_log(case_log, attributes)
+      case_log.save!
+    rescue ActiveRecord::RecordNotUnique
+      unless attributes["old_id"].nil?
+        record = CaseLog.find_by(old_id: attributes["old_id"])
+        @logger.info "Updating case log #{case_log.id} with legacy ID #{attributes['old_id']}"
+        record.update!(attributes)
+      end
     end
 
     def compute_differences(case_log, attributes)
@@ -172,10 +185,16 @@ module Imports
       attributes.each do |key, value|
         case_log_value = case_log.send(key.to_sym)
         if value != case_log_value
-          differences.push("#{key} #{value} #{case_log_value}")
+          differences.push("#{key} #{value.inspect} #{case_log_value.inspect}")
         end
       end
-      raise "Differences found when saving log #{case_log.id}: #{differences}" unless differences.empty?
+      @logger.warn "Differences found when saving log #{case_log.id}: #{differences}" unless differences.empty?
+    end
+
+    def check_status_completed(case_log)
+      unless case_log.status == "completed"
+        @logger.warn "Case log #{case_log.id} is not completed"
+      end
     end
 
     # Safe: A string that represents only an integer (or empty/nil)
@@ -332,10 +351,12 @@ module Imports
       end
     end
 
-    def previous_postcode_known(xml_doc)
+    def previous_postcode_known(xml_doc, previous_postcode)
       previous_postcode_known = field_value(xml_doc, "xmlns", "Q12bnot")
       if previous_postcode_known == "Temporary or Unknown"
         0
+      elsif previous_postcode.nil?
+        nil
       else
         1
       end
diff --git a/app/services/imports/import_service.rb b/app/services/imports/import_service.rb
index bd48dc8a3..3f319b358 100644
--- a/app/services/imports/import_service.rb
+++ b/app/services/imports/import_service.rb
@@ -14,7 +14,7 @@ module Imports
         xml_document = Nokogiri::XML(file_io)
         send(create_method, xml_document)
       rescue StandardError => e
-        @logger.error "#{e.class} in #{filename}: #{e.message}"
+        @logger.error "#{e.class} in #{filename}: #{e.message}. Caller: #{e.backtrace.first}"
       end
     end
 
diff --git a/db/migrate/20220425143130_add_old_id_and_index_to_case_logs.rb b/db/migrate/20220425143130_add_old_id_and_index_to_case_logs.rb
new file mode 100644
index 000000000..882a77f43
--- /dev/null
+++ b/db/migrate/20220425143130_add_old_id_and_index_to_case_logs.rb
@@ -0,0 +1,8 @@
+class AddOldIdAndIndexToCaseLogs < ActiveRecord::Migration[7.0]
+  def change
+    change_table :case_logs, bulk: true do |t|
+      t.column :old_id, :string
+    end
+    add_index :case_logs, :old_id, unique: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index dcd9e007a..40cd9cd83 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2022_04_21_140410) do
+ActiveRecord::Schema[7.0].define(version: 2022_04_25_143130) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -219,7 +219,9 @@ ActiveRecord::Schema[7.0].define(version: 2022_04_21_140410) do
     t.integer "old_form_id"
     t.integer "lar"
     t.integer "irproduct"
+    t.string "old_id"
     t.index ["managing_organisation_id"], name: "index_case_logs_on_managing_organisation_id"
+    t.index ["old_id"], name: "index_case_logs_on_old_id", unique: true
     t.index ["owning_organisation_id"], name: "index_case_logs_on_owning_organisation_id"
   end
 
diff --git a/spec/fixtures/exports/case_logs.xml b/spec/fixtures/exports/case_logs.xml
index a5dd626af..e837ae266 100644
--- a/spec/fixtures/exports/case_logs.xml
+++ b/spec/fixtures/exports/case_logs.xml
@@ -161,6 +161,7 @@
     <old_form_id/>
     <lar/>
     <irproduct/>
+    <old_id/>
     <providertype>1</providertype>
   </form>
 </forms>
diff --git a/spec/services/imports/case_logs_import_service_spec.rb b/spec/services/imports/case_logs_import_service_spec.rb
index 111106f31..467c06f38 100644
--- a/spec/services/imports/case_logs_import_service_spec.rb
+++ b/spec/services/imports/case_logs_import_service_spec.rb
@@ -5,8 +5,6 @@ RSpec.describe Imports::CaseLogsImportService do
   let(:fixture_directory) { "spec/fixtures/softwire_imports/case_logs" }
   let(:case_log_id) { "0ead17cb-1668-442d-898c-0d52879ff592" }
   let(:case_log_id2) { "166fc004-392e-47a8-acb8-1c018734882b" }
-  let(:case_log_file) { File.open("#{fixture_directory}/#{case_log_id}.xml") }
-  let(:case_log_file2) { File.open("#{fixture_directory}/#{case_log_id2}.xml") }
   let(:storage_service) { instance_double(StorageService) }
   let(:real_2021_2022_form) { Form.new("config/forms/2021_2022.json", "2021_2022") }
   let(:logger) { instance_double(ActiveSupport::Logger) }
@@ -14,24 +12,37 @@ RSpec.describe Imports::CaseLogsImportService do
   context "when importing users" do
     subject(:case_log_service) { described_class.new(storage_service, logger) }
 
+    def open_file(directory, filename)
+      File.open("#{directory}/#{filename}.xml")
+    end
+
     before do
       # Stub the S3 file listing and download
       allow(storage_service).to receive(:list_files)
                                   .and_return(%W[#{remote_folder}/#{case_log_id}.xml #{remote_folder}/#{case_log_id2}.xml])
       allow(storage_service).to receive(:get_file_io)
                                   .with("#{remote_folder}/#{case_log_id}.xml")
-                                  .and_return(case_log_file)
+                                  .and_return(open_file(fixture_directory, case_log_id), open_file(fixture_directory, case_log_id))
       allow(storage_service).to receive(:get_file_io)
                                   .with("#{remote_folder}/#{case_log_id2}.xml")
-                                  .and_return(case_log_file2)
+                                  .and_return(open_file(fixture_directory, case_log_id2), open_file(fixture_directory, case_log_id2))
       # Stub the form handler to use the real form
       allow(FormHandler.instance).to receive(:get_form).with(anything).and_return(real_2021_2022_form)
     end
 
     it "successfully create all case logs" do
       expect(logger).not_to receive(:error)
+      expect(logger).not_to receive(:warn)
       expect { case_log_service.create_logs(remote_folder) }
         .to change(CaseLog, :count).by(2)
     end
+
+    it "only updates existing case logs" do
+      expect(logger).not_to receive(:error)
+      expect(logger).not_to receive(:warn)
+      expect(logger).to receive(:info).with(/Updating case log/).twice
+      expect { 2.times { case_log_service.create_logs(remote_folder) } }
+        .to change(CaseLog, :count).by(2)
+    end
   end
 end