Guern,
The argument runs that there is no direct military threat to the UK and there will not be one in the forseeable future. Thus "value for money" calls for us to operate from fewer bases, thus reducing fixed overheads.
Particularly in times of tension, our bases could still be vulnerable to terrorist threat. However, operating from fewer bases allows us to concentrate our ground defences. There is inevitably an associated risk and this has to be "managed".
IMHO I think it is a logical approach. Our numerous airfield spread over the UK originate mainly from WW2 and were necessary to provide survivability against the Cold War threat. The world today is a different place and personally I think the average terrorist is more likely to go for softer and more high profile targets in the UK.
However, the lack of different places to get posted (even if only within the UK) is a definite loss (especially as I love Morayshire!)