Riding lessons

I'm a new convert to biking (passed test 6 months ago) and am totally hooked. The only thing that annoys me a little bit is that I appear to be crap at it. I've got a great bike IMHO (Triumph Sprint RS 955), and can keep up with or catch most things on a straight, but I get left behind through corners. I don't want to be a mental rider - just a little more competent

Has anyone tried any of the rider courses advertised in biking publications ? any recommendations ?

Possibly it's just my lack of experience which will only come with time I suppose.

Sjm