Should have nabbed your old mans bike last Friday Kel and started at Cadwell
There is a thread about this somewhere in the trackdays section from a while ago. I normally suggest Brands Indy as a good place to start. It's got a blend of all sorts of different corners but most importantly, I think, is that as it's a short circuit you'll get plenty of laps in so it won't take too long to learn where you're going and to get comfortable.