There is the National Rural Touring Forum
They cover pretty much the whole country, I think - there is a separate, slightly different scheme for Wales. Often have a number of folky acts included.

The way it tends to work - the regional administrator complies a 'menu' for the season from acts she has selected, from all those who have approached the scheme. The local promoters then select who / what etc they want to put on. Usually village hall gigs with lovely people, who do their best to make everyone have a good time - including the band.