Andy_S :
My apologies, you are of course right, I meant to say south of Birmingham - i.e. I am considering London civilian airports only.
Manston is not a London airport, so why target a London market?
But you clearly have not looked at my earlier 3D maps of Kent, which make it clear that from any of the 12 Category A London main-line stations, by road or by rail, now you are in the air quicker via Manston than via Heathrow. So of course Manston should be considered a London airport. This is the key point that the changes in road and rail links have made - There is no point looking back 10, 20 years in history. No Manston is not now just a Kentish airport, it is a ****-hot London airport.
The last two owners made no attempt to exploit these changes as they happened.