I thought I'd post this as it might be useful to anyone else in a similar position.
I have an hour and a half left on one of my items, and noticed there were a couple of bids so I checked the feedback...it looked Ok initially at 3, but on closer inspection most of the feedbacks said 'time waster' and 'non payer'
So I decided I'd try and cancel their bids before they wasted my time too - I didn't think I could but it was really easy.
You just click on Help, search for cancel bids or similar and it comes up with a link, then you get to cancel the bids of the person in question, however near the end it is.
I've added them to my blocked list from the same page as well, so they can't bid on my things in future.
Hope this is of use to someone. Some buyers aren't worth the trouble.