Hello Genghis,
If there are active RAeS branches here, it's news to me. I was an associate member (AMRAeS, right?) from 1996 to 2001 or 2002 (can't remember exactly), and there's nothing doing in Canada (or the USA).
I believe that the Society is active in other parts of the Commonwealth, however (e.g. Australia, NZ, S. Africa).
Eventually I realized that all I was getting for my membership fee was a (not very good) magazine, so I let things go.
£102 p.a. is better spent on flying, in my case anyway.