Very very good! So, which one of our esteemed colleagues here put that together?! Good on you...
The trouble is, the Govt have got themselves caught in a cleft stick - what alternative to the military do they have for manning fire duties? None, as far as I'm aware.
If the military are the only publicly paid resource the Govt has that HAS to do as directed, with no possibility of refusal, of course they are going to use them.
When you try to imagine the conversations that take place in some room on Downing Street - "They will provide cover Admiral" - "No, they won't Minister" - "Fine, I'll replace you with someone who will say yes" - what chance does the military have?
Unless the individual at the top refuses a direct order, or the whole top two echelons resigns to a man (would have to be to a man, wouldn't it, because I don't supppose for a single second there is a woman holding that rank I'll save that fight for another time) then there is absolutely no way out, except for individual service people to leave their jobs.