Hi Aldamski,
I live in Dorking, the place in Guildford is informally called Barry's airfield which is also a campsite. I haven't been there for quite some time so am not sure what it is like these days. However myself and another guy I met recently fly occasionally from local friendly farmers fields around the Mole Valley area.
The trick is keeping access to those fields by not over using them or causing any problems for livestock etc. A fear of losing access due to such over-use is why people tend not to share their location publicly on forums like this. However, building up a good rapport with local land owners is the best way to start, most have a weak spot for free bottles of wine or other such fine things.
Nick