In answer to the question as to where the one is based around Leicester, I'm fairly sure that it's the one from Spanhoe, about 1/3 of the way between Peterborough and Leicester. They have one there, but I'm not sure what it's used for.

I had much the same problem with Edwards AFB for quite a while, until I then decided to reinstall FS onto this computer. To this day, I still haven't sorted out what was wrong with it. I tried various scenery files, AFCADs, scenery layerings... you name it... but still nothing - just a load of F16s,...