Near Cranleigh, how about you? I know the green lanes along that route from a mountain biking point of view but I've not been along there in my Landy as I'm not totally equipt for offroading/green laning yet.
Its definately too dodgy if your on you own, not recommended.
Check out the Green Laning section there's a thread for Surrey Green Lanes. There seems to be good amount of stuff going on there.
Post some piccies of your pender and I might see you around.