oh and to answer your questions:
If you do can you tell me what the riding is like? see my post abouve
Any good hill climbs; yes, you are on the North Downs and close to the Surrey Hills so you can go up and down both of them. Box Hill has plenty of long climbs to grind up
rocky, single track? rocky if you want, plenty of singletrack
Are they natural or man-made? North Downs is mainly ‘natural’ Surrey Hills has a few more man-made trails
I’ve seen one route for Cockshot hill and there a few dug-in jumps, is that the norm there? Cockshot Hill is a small area that is mainly parkland, not really ideal for MTB. there are plenty of dirt jumps all over the area if that is what you like but you seem to be looking for more mtb rather than BMX stylee
Also are there any long routes? yes, see above
Why dont you keep an eye out on our ride diary and join us next time we go out?