Wld ,[allkinds of basic coperation are routinely witheld]by whom, not by me,I used to book Brimstone when I ran a folk club.
Unaccompanied traditional singers have the same problem that i think you are describing, as well[Dartford Folk club].some clubs have definite booking policies[those that generally book the likes of DBrimstone are not going to book KevinMitchell].,and vice versa.
it is adouble edged sword,it cuts bothways.so stop being paranoid.