Missing attachment "paper clip" icon in Mac Mail

So I just spent nearly an hour on the phone with Apple Support.

The only solution is to convert your POP account to IMAP. You can create a new account as IMAP and then drag and drop your mail from the POP account to the IMAP account.

The plus is that the problem is fixed but the minus is that the mail stays on the server, which will cause a problem with server space going forward. For the moment I will keep both accounts and use the IMAP but keep the POP to delete from the server.

There is no real chance of the Paper clip issue being fixed for POP.

Yes, the attachment icon is there for IMAP accounts, but not for POP. That is the problem as you can't delete attachments if the Mail app does not recognise they are there.

Thanks. Your link doesn't work on the first one but I did try another account with the same result. I have also tried safe mode. Unfortunately neither solves the problem. It appears to be that the Remove Attachments feature just does not work for POP accounts, as many other have posted the same problem.