Thankyou everyone for your helpful advice.
Yes I was doing the same as Jen and reading emails on my desktop pc as well as hudl.
I went away for a few days (plus hudl) just after I bought it and everything was fine, the problems started when I got home (and was reading emails on main computer as well).
My main computer is set to receive emails via POP3 and I have changed the hudl to this from IMAP, this brought up the option Delete email from server NEVER which IMAP didn't.
Many thanks once again
Caro