In the grass north of the runway, you can see a pattern of scars, all the same length, mostly orthogonal, and a few diagonal. These are almost surely archaeological trial trenches:
Often these are dug to evaluate land before it is built on, in case there is important ancient stuff that will be disrupted or buried. That hints that the airfield may be about to be redeveloped.
You are very likely right; every few years I look it up to see what's happened to such a large chunk of undeveloped land right next to one of the main A roads into London. Here's the current first hit on Google (for me):-
https://www.borderarchaeology.com/services/archaeological-ev...
Often these are dug to evaluate land before it is built on, in case there is important ancient stuff that will be disrupted or buried. That hints that the airfield may be about to be redeveloped.