Hi Dan, only just seen your thread, I live in West Sussex, close to Gatwick airport and ride mostly on my local trails around Tilgate forest, and occasionally in the Surrey hills, Bedgebury and South downs.
Unfortunately I’m having a bit of an enforced lay off at the moment due to carpal tunnel syndrome that make cycling both painful and difficult (can’t feel my hands and operate brakes after about 20 mins) but I’m due to have surgery soon so should hopefully be back on the trails in the new year.
May I recommend looking up the guys and girls from Sussex muddy arse, several of them post on here and they’re a friendly bunch who have monthly club rides and their own forum to arrange more casual weekly rides.
My e mail is in my profile if you want to get in touch.