Well, condensing what has been said in the links above it appears that most clubs contain fairly normal people and are usually quite friendly. Basically, its a case of make contact, sound them out to see if you like them and what's on offer (and vice versa) and make a decision about returning from there.
The fact that most require an audition is a little daunting, especially for someone like me who does not do cardy things (though I have been known to do 'jumpers'

). I'm up for learning card & coin etc but with my initial/original interest being in other areas I think it would be difficult to perform something different each time if they expected a themed trick. I suppose i could handcuff them to a chair and hypnotise them into believing I was the the greatest thing but somehow suspect that would wear thin.
I suppose the only way to discover if a club is geared to my (or anyone else's) particular level or interest is to make the first move and find out. Exactly the same re finding out whether the members are the sort of people you want to associate with. For me, I'm just looking for a sociable evening and occasional special event based around a rather odd interest I possibly should have outgrown about 30 years back; learning some new skills would be great as would sharing my knowledge (even if not directly magical). It's obviously the personality, friendliness and overall quality of the other members which is the main factor. I can go down the pub if I just want to hang about with {Insert own ending].
Rest assured that if I walked into a room with a load of middle-aged men dressed in fezs, waving wands and with their right trouser leg rolled up I'd be off in a flash!!!
Thanks to all who've contributed.