I just joined and mine took at least 7 weeks just to go through on the credit card let alone actually receive anything. I had a similar dilemma to you coz i was beginning to think it had got lost in the post!!! However, i was glad i hadn't wasted my and their time by trying to contact them because about a week later, my membership card arrived with a letter, postcard and OWN guitar pic. So, in my experience (v. limited but also very recent) you don't have to wait until newsletter time, but it does take a long time so you need to be patient (especially coz they are completely flooded with applications with a tour coming up).

Hope this helps.