"I learn 10 -15 new songs a year, most very recently written but then I go to a 'folk club' and up gets a floor singer who churns out stuff he was churning out 30 years ago and then in a very sloppy manner.
It really brasses me of when this happens and I feel the paying audience is being short changed"
Each to their own I say, it takes different types to make a folk club work and not everyone likes a whole evening listening to songs they don't know. Why shouldn't he sing what he wants to sing and how do you know that the audience is being short-changed - or is it just your opinion? (which you have every right to hold but lets not mistake that for the audience's opinion).
If you are used to singing your stuff to a different audience you shouldn't be too surprised if folk club attendees sing stuff that is older and traditional.