Depends what sort of riding you want to do. There’s not a huge amount of the sort of riding that would justify a Stinky on Leith Hill TBH.
If you’re just into jumps, drops, etc then you might be OK but I’d have thought a 6in travel trail bike like a Lapierre Spicy, Spec Enduro, etc would handle even the biggest local stuff and would be much more fun to ride on the singletrack that makes up most of the Surrey hills riding.
You’ll need to hook up with others to find the good stuff. Try asking at Nirvana, Head for the Hills and Pedal & Spoke about local rides.
BTW what’s wrong with the attitude of BMXers?