Like others I'm a bit bemused by the term "ethnic English music" But, good luck with your research, For all things traditional, you need travel no further than the archivist Doc Rowe....100s of thousands of photos, videos, audio recordings etc, garnered over decades of painstaking collecting. Has just moved his entire archive to Whitby. Also it might be worth checking out John Adams who runs the Village Music project in Yorkshire (and pops in here occasionally )
Also worth checkng out Rod Stradlings site...Musical Traditions.
A treasure trove of information.
Let us know how it goes, I fear you might be some time over this one!!!