I've had a 'mole' as long as i can remember.gp said it was nothing to worry about as it was a wart.how can he tell between a wart and a melanoma ?

Mole vs wart: Melanoma is an aggressive dangerous form of skin cancer. If something has been sitting on ur skin for sometime without any major changes I wouldn't worry at all. I doubt it's truly a wart because after 2 yrs it should disappear. Probably it is a mole or pigmented skin lesion. U can watch that for changes over the years, and if it changes then do something about it. See a dermatologist if in doubt.