If you get the chance to join a military club go for it, lots of advantages, some disadvantages, but in general there are more advantages. As with any club, go and see them and make your mind up based on what you see and feel about it.
You get up to 10 hours max credit for gliding based upon 10% of you PIC time in gliders so you would need 100 hours to get 10 credit.
The PPL increased to 45 hours in 1999, the wonders of Europe! As most people take longer its not a big issue. Silver C credits ceased at the same time but still apply to the
NPPL.