Thanks for your replies, which have served to convince me to go ahead and get it checked out. I only hope the doctor is willing to have it investigated - I read somewhere that many MD's are not well versed in oral cancers if they are not 'obvious'.

For what it's worth the dentist noted that I had several sores dotted around my mouth; I believe that's what led him to say "don't worry, you are prone to these". None seem to form the 'classical' signs I read about (no white patches, no smooth red patches either) but at the same time, as you've noted, they shouldn't be kicking around for so long.

I will be sure to let you know the upshot...

Many thanks
Mike

(by the way kcdc, I always get taken for an Australian when I'm in the U.S. - not quite sure why that is!)