diff --git a/perllib/FixMyStreet/Cobrand/Bromley.pm b/perllib/FixMyStreet/Cobrand/Bromley.pm
index ea661e4d2f..d2648433b3 100644
--- a/perllib/FixMyStreet/Cobrand/Bromley.pm
+++ b/perllib/FixMyStreet/Cobrand/Bromley.pm
@@ -581,7 +581,7 @@ sub should_skip_sending_update {
         my $echo = Integrations::Echo->new(%$cfg);
         my $event = $echo->GetEvent($report->external_id);
         if ($event->{ResolvedDate}) {
-            $report->update_extra_field({ name => 'Event_ID', value => $event->{Id} });
+            $report->update_extra_field({ name => 'Original_Event_ID_(if_applicable)', value => $event->{Id} });
             $report->set_extra_metadata('open311_category_override' => REFERRED_TO_VEOLIA);
             $report->set_extra_metadata('echo_report_reopened_with_comment' => $update->id);
             $report->unset_extra_metadata('external_status_code');
diff --git a/t/cobrand/bromley.t b/t/cobrand/bromley.t
index 4075c0cb79..b7d5526e8e 100644
--- a/t/cobrand/bromley.t
+++ b/t/cobrand/bromley.t
@@ -933,7 +933,7 @@ subtest 'redirecting of reports between backends' => sub {
             my $req = Open311->test_req_used;
             my $c = CGI::Simple->new($req->content);
             my $detail = $report->detail;
-            is $c->param('attribute[Event_ID]'), $event_id, 'old event ID included in attributes';
+            is $c->param('attribute[Original_Event_ID_(if_applicable)]'), $event_id, 'old event ID included in attributes';
             like $c->param('description'), qr/Closed report has a new comment: comment on closed event\r\nBromley pkg-tcobrandbromleyt-bromley\@example.com\r\n$detail/, 'Comment on closed report included in new report description';
         };