Escaping the M25

Well, this thread has generated some useful advice.

I've recently moved to Tooting, and now the weather is improving i'm planning on getting out into Surrey and doing some longer road rides, does anyone know of any nice routes out of south-west London and beyond the M25, preferably on quieter roads?

You could join one of the club runs of the biggest cycling clubs. They tend to have separate groups for newbies and you might be able to tag along. Club riders know the local lanes extremely well and can show you a few good tips to get you started, and you may of course find the club companionable enough to want to join it.