Any help on this would be really appreciated, I've been with Plusnet for years but if I can't resolve this quickly I'll have to leave as I'm losing work. I'm using an email address with a suffix of a domain hosted by Plusnet.
Work mails were not arriving, tried a few things but eventually I gave up and turned off all my spam settings. All emails (I think) now arrive and my inbox is much more interesting 
See question Question #200265432
https://community.plus.net/t5/Email/Bounced-emails/m-p/1730332#M30734
However, now (assume it's not a coincidence but I don't know) some / many (I'm not sure) emails I send are arriving at destination in the users trash box so often not found (more than one user e.g. one UK, one Serbian, they weren't previously goig into trash). I sent out a pile of emails today to non-business addresses asking for confirmation of receipt and all were received so it would appear to be only some (and only business) destinations are an issue.