Coconutty, Love the name and the 'icon'.
Thanks for your help. As the complete IT technophobe, I thought I'd disable NAV, download a trial version of Kaspersky AV and run that since it was their online scanner that found it in the first place. Happily, it found it and offered to deal with it - an offer which I happily accepted. I hope that's it now!
I don't understand why NAV fails to deal with this sort of thing!
Cheers,
mcdhu