For what it is worth,

Although the question is about current English folk clubs, it might be useful to remember that in the states the "folk" presentation/preservation/revival movement(s) have a long and complex history.

Ethnic diversity was not always a goal, much less perceived as desirable.

In the states, if you look at the "folk" phenomenon as a whole, "folk" has often been used in an exclusive rather than an inclusive sense. Often it has meant the traditional music of those of anglo/irish/scots descent.

A fascinating discussion of the political side of the folk movement in the states is "The White Top Folk Festival: What We (Have Not) Learned" by David E. Whisnant
http://www.h-net.org/~appalach/Whitetop3.html

IMHO If you want to understand why things are they way they are it is often useful to know how they used to be.

Russ (Semper GUEST)