You have these setup:
k2._domainkey.legacyantiques.co.uk.legacyantiques.co.uk. 3276 IN CNAME dkim2.mcsv.net.
k3._domainkey.legacyantiques.co.uk.legacyantiques.co.uk. 3276 IN CNAME dkim3.mcsv.net.
What you probably want is:
k2._domainkey.legacyantiques.co.uk. 3276 IN CNAME dkim2.mcsv.net.
k3._domainkey.legacyantiques.co.uk. 3276 IN CNAME dkim3.mcsv.net.
So in the field named Subname only enter k2._domainkey, k3._domainkey respectively.
The _dmarc record seems to be ok (if slightly different than what you wrote above):
_dmarc.legacyantiques.co.uk. 3276 IN TXT “v=DMARC1;p=none;sp=none;”
HTH
fiwswe