The Ballad and Blues Club was not the only one with that policy. When I started geting around the folk clubs of the North East some forty years ago, while the rule was not exactly insited upon with a rod of iron, you were certainly "encouraged" to sing the folk songs of the British Isles. Then when The Barleycorn folk club opened in Newcastle in 1969 co-presenter John Revie, a MacColl associate from way back, did insist that songs should come "from your own cultural media". No bad thing if it got people exploring their own traditions and better still exploring the traditions of their native area(in my case the North East).
While agreeing with the Alex Campbell omission, did I miss it or was Dominic Beahan not mentioned either?