Pip Radish

Mainly because we've got this word 'folk', and most newcomers aren't likely to know that it can mean two almost completely different things.

Only two? Yes, that is the situation as it exists and (deep breath) there is absolutely nothing that you can do about it. The club you describe is not going to stop calling itself a folk club just because you tell it it is not conforming to the 1954 definition so stop agonising over a couple of words and concentrate on the music. Go to the clubs that sing and play the music you like and recommend them to anyone who shows an interest.