Opinions cunningly disguised as great thought...
I think;
if it's dedicated to the British and Commonwealth side of things, it might be a good idea to name it as such (eg: B&CWW2 Soc.).
you might consider founding it on either the 3rd of Sept next year, to tie it in with the start of the war and the 70th anniversary.
a cracking newsletter is a must really, something which members go "wow" when they get it. Would this be printed, web pdf or both?
the AGM is a good idea, I'd suggest tying it in with a big event or venue (eg War & peace, IWM, etc) so that it also offers a good promotional opportunity for the soc. as well as the original function. It might be a good idea to move the event/venue to get a wider reach.
it's worth considering linking the expertise of the membership with the chance to make simple WW2 presentations at schools. A few "generic" presentations could be created to be given all over the place by members. It's not a great earner but it would boost funds a little. It might also open the doors for further funding from a third party.
cheers,