Or they've just spent the last 10 years moving around the country, sick of living in towns they don't want to be in
Then why express in interest? The EOI is base specific.
The problem they are having with crewing the new bases is partly people putting in an EOI for bases they were only "sort of" interested in anyway. The rest is due to Cobham. They expect you to submit an EOI for a base (several months ago) then tell you nothing until a few weeks before you are expected to move, at you own expense, at Christmas time. I would be inclined not to sign any base transfer paperwork too.
As for the turbo-prop guys and girls: throw your hat in the ring, like the rest of us and take whatever base you are given, like the rest of us. If you have so many other good options available to you, be my guest.