Have you reported your issues to eUKhost? I'm on the cPanel Shared Hosting account and they had to roll back my cPanel theme from 11 to X to improve the spam filters (ironic hey?) because there was a bug in the theme that caused them to fail (?)
It's a shame that there isn't a 'central' email account for spam mail that we can all send stuff to so the filters can learn about the types of spam messages that we are receiving - it works great for my ISP.. if I get any spam, just forward it to them and the spam filter learns it.
Regards
James
BoyFresh Media
www.boy-fresh.co.uk