Oh, does that include Irish, Scottish, Romany, and Traveller? What about a chap (young to me, I imagine about 30) I know from Brittany who has lived in London for several years and is (after a LOT of prodding promising to bring us some traditional Breton folk songs at next year's Sweeps' fest? And why do they have to be young? Or indeed snigger snogwriters? Might they not be folksong singers? And why is the background more important than the ancestry? My girlfriend's father is from the Republic of Congo but she was brought up in England by her mother who is English/Irish/Traveller/Cockney/might be a bit of Hungarian in there too. What is her "background"? - I'd opt for English and she even has a tattoo saying "Made in England", although people always ask her "Where are you from" and look very puzzled when the reply is "Crayford".   

This enquiry all seems rather a construct.