I'm sure I've read somewhere that the MoD had revealed outsourcing company, Capita, had brought in fewer than 1 in 10 of the recruits needed by the army. Even if these overseas bases were built who would man them?
I think you are more likely to have delusions of what the modern British Army looks like, they would most likely man these bases with the well trained and experienced soldiers they have already. Its only the raw recruits that are dwindling - most likely because it's too tough a prospect for many of today's generation (but that's another thread).