Oil leak....

Hi there, I've just purchased a P reg Polo, which has done 49,000 miles, has full service history. Most recent service was December last year. I got my old man to have a good look over it before I made the final decision to buy it, and he thought it was all in good order. The only thing we noticed was a small oil leak around the left side of the roca-cover (not sure if thats the correct spelling). My old man insists it is nothing to worry about and should be easy to fix. But just for my own piece of mind I was wondering if anyone could tell me what this is, and whether it is common on Polo's of that age. Could it be an oil seal? I trust me old man or I wouldn't have brought the car, but I still would like to know if anyone else has seen or had the same thing?!

Cheers Smile