Location signs up on the roads approaching Swinley recently, saying (I think) ‘DBL‘.
Haven’t seen any in Swinley or pointing into the estate, but at least directs down Nine Mile Ride towards The Look Out.
Also, the other week, there was a sign on the junction of Shere Road where the A25 turns right up the hill towards Newlands Corner that simply said ‘BASE‘, pointing towards the hills. A typical base camp sign for a location. Didn’t have time to check it out.
Update: Not sure if it’s related but further into the hills on the back roads towards Peaslake are signs up saying ‘MAYDAY‘.
This I assume – http://www.getsurrey.co.uk/news/s/2113265_mayday_call_for_dorking_as_tv_thriller_filmed