I flew into Fairoaks for the first time yesterday (also from Biggin).
The tower are very helpful, definately worth giving them a call. The briefing will take you through the somewhat unusual airspace here (Fairoaks is actually inside the London TMA). circuits are at 1100ft on QNH (at least for rwy 24), and you are encouraged to join overhead as close to the 1500ft ceiling as you are comfortable.
Approaching from Biggin, I talked to Farnborough on 125.25 and flew direct to the OCK VOR. I made sure I was down to 1400 feet over OCK and contacted Fairoaks (by this time the field is clearly in sight). Then the rest is easy.
Have fun (and I don't be afraid to try longer trips from Biggin - once you get past Farnborough the airspace is much easier...)