Hi Paul,
Thanks for your reply. I am not receiving anything at all about the emails, and the senders are not receiving a "bounced back" message either.
I asked one of them to try another email address (gmail) and it worked no problem. The file was a JPEG and was not particularly large (2MB) so I don't understand why it wasn't delivered to my Virginmedia address.
I have checked my Junk folder but they are not there either.
Thanks,