The tradition in England was to sing unaccompanined. That's what collectors like Cecil Sharp found.

I imagine that there was a certain amount of informal harmony singing - after all if the pitch of the singer is not right for your voice it is sometimes fairly easy to sing a fourth or a fifth away. I find myself doing it without realising. At a recent weekend workshop I was several times asked to sing up a fourth :-) There were just three men in a group of 25 and the other two were tenors so I was on my own singing the bass line.

I saw the Watersons way back in the 60's and was very disappointed. I had heard many good things about them but I found their performance lacked variety. They sang everything at the same, moderately slow, tempo, all very serious with no lighter songs to make for variety. I think they were much too earnest in those days - even for an earnes student like I was in those days. They may have lightened up in later years, but that performance put me off completely and I never bought an album or wanted to see them again.