+1 for the Scots Music Group. It's a very good environment for learning, although I found the emphasis on learning by ear difficult (I'd been taught to play music by reading notation).
You might want to try out the Slow Session class run by the excellent Nigel Gatherer. There's usually a Slow Session in a pub after the class (you don't have to be in the class to go to the session of course).
Nigel also runs various workshops for mixed instruments throughout the year. His Mixter Maxter days are excellent fun. Nigel has arrangements of various tunes on his website and has some very good tunebooks to buy as well.
One to One tuition might also be a good way to develop playing skills early on and avoid bad habits. As an adult learner (mandolin), I found lessons very helpful and the guy I went to for lessons was a hugely interesting individual and introduced me to a wealth of music I'd never considered before.
Once you've really got going, you should consider checking out the Edinburgh Mandolin and Guitar Orchestra (EMGO). Mixed and varied musical repertoire and lovely people to play with. They've got some footage on YouTube I think and a lot of recordings on SoundCloud.