I refuse to believe that there aren't pubs some parts of the country that aren't screaming out for mid-week custom and wouldn't be more than happy to let (or even give) a reasonably quiet corner or side room for a monthly session
In the Home Counties, South East and South Midlands unlikely. Most want to fit in as many covers as possible for the meal trade.

Personally I regret the decline in the classic folk club format (ie weekly guest + floor spots) but the scene has moved in other directions. There are still a huge number of opportunities to experience good folk music either as an audience member or as a participant.