I recently tried it in both, but I have just removed from Admin page / Aliases and now its only in Filter “send message copy too” : user@theaccountant.co.uk
Have just tested and still getting same error message, I have mulled the data to remove most of personal information:
Reporting-MTA: dns; mail.domainblarblar.com
X-Postfix-Queue-ID: C87F41A106B
X-Postfix-Sender: rfc822; scott@testing.co.uk
Arrival-Date: Wed, 6 Mar 2019 13:40:49 +0000 (GMT)Final-Recipient: rfc822; user@theaccountant.co.uk
Action: failed
Status: 5.7.1
Remote-MTA: dns; spamtitan2.ntssecure.com
Diagnostic-Code: smtp; 550 5.7.1 user@theaccountant.co.uk: Recipient address
rejected: Please see
http://www.openspf.net/Why?s=mfrom;id=scott%40customer.co.uk;ip=89.40.111.123;r=spamtitan2.ntssecure.com