Have a listen to Salt of the Earth - a wonderful, if short-lived 2 man 2 women group from NE UK. Amazing harmonies plus occasional concertina. They were Danny & Joyce McLeod + Barrie & Ingrid Temple - it was a real shame when they went their separate ways after just one CD (Turn of the Tide). Glad i saw them though. Follow this link and find them amongst 'artists'

http://www.chanteycabin.co.uk/