I really sympathise with young people in the armed forces trying to buy a house. When I bought my first house in 1971 I was on £2,500 pa as a Flying Officer (inc flying pay) and my house cost me £5,100 - say 2 years salary. The mortgage was easily manageable on my single salary (wife heavily pregnant thus not working).
I've just Googled prices for similar houses in that area and see they are around £180,000. I'm a little out of touch with service pay, but I'm guessing a Flying Officer isn't yet on £90k (no idea how much in fact) so buying a house is much tougher, so I'd approve of any help they can get, however little it may seem.