Biggus:
All Helos will be Army/Joint RN. Possibly RAF personnel seconded like the Carrier aircraft.
The other bases are likely to close. Not sure about the Reds, but when all RAF airshows are cancelled in SDSR then........
As stated earlier, there will still be some other non-flying units but I have just given my take on the flying bases. For example, Cranwell will remain for ground training but the airfield may well be "privatised" for training (if it stays open).