Skydriller,
There are a number of issues that are a clear threat to the future of GA at Biggin, most notably the proposals for the new housing development near the airport. When I say near, I do mean near have a look at this:
That yellow area will be 139 homes (at current estimates) and do you honestly think it'll take them long to get really, really cross when they realise that there are people actually having the audacity to fly them aeroplane thingies from that airport thingy next to their shiny new Barratt/Wimpey/McHome?
BH