Anyone know of any decent trails/singletrack, etc?

Reigate is a great base for riding the north downs ridge, some really nice stuff, just join up the bridleways as they go up and down 🙂

Try the singletrackwolds very own 'Trail Guide'. They've got routes on the north downs/surrey hills area and the south downs.

http://www.singletrackworld.com/trailguide/uk/south-east/the-north-downs/

http://www.singletrackworld.com/trailguide/uk/south-east/the-south-downs/

Surrey Hills are better than the North Downs, you'll have to come slightly further West, Wescott is a good starting point. You do really need to know where you're going though!

Crawley: Tilgate Forest…

lol @ Tilgate.

I'm reasonably new to the area, but have been out with some locals and recorded the routes on my Garmin.
Email in profile if you fancy a spin, either on or off road.

Stew you've got a very rich little pocket of riding down here on the Surrey Hills and the north downs although as Njee says, they aren't quite as good as the surrey hills. Westcot is a good starting point for Leith Hill but it's not as user friendly as say Peaslake where you should be able to follow other groups or befriend someone who knows their way around. Peaslake gives you easy access to Holmburry Hill and Pitch Hill.