Thanks Joe,
I think it likely that the source of the version I know came from either the 'Gentle Angry People' book or wherever the A.R.M. got it.
Although our vicar wasn't a Methodist, he did do an MA at the Urban Theology Unit at Sheffield in the 1980s so that seems a good connection.
Perhaps tracking down an old A.R.M. member would bring the song book to the surface. I feel sure that some Methodists are still radical.

"Green are the leaves and merry is the May,
long is the night and the winter that is over"

The song popped into my head as I was cycling along today.