It sounds like there is more than one vision of what you are trying to do:
1) provide background music to a group of people who did not come to hear you and may not be interested
2) providing a venue for folkies to share music
These are rather different. I would think that each group would need to decide what it is trying to do. Therefore when starting a new folk club, and I am not entirely sure what that term really means in the UK, the initiator(s) would need to decide the purpose of the club before searching for a venue.