"Folk music is not just suitable to be played in any venue at any time, and that is why we have folk clubs.
you try singing half an hour of songs such as tifties annie in a working mens club"

It could still be a folk club although it is being held within a working men's club, of course. The club would just hire or use a suitable room on a night when it was free. Many folk clubs do, in fact, meet in clubs. Bowling clubs, for some reason, seem to be very popular for this sort of thing in Scotland.