Though this song seems to have been found once only in tradition, almost every time it has been published in print or on a recording the title has been given differently, which may cause some confusion. Here is (I think) a full list:

Banks of the Mossen
Banks of the Mossem
Banks of Sweet Mosson
Banks of the Sweet Mosson
Banks of Sweet Mossing

Roud Folk Song Index number 1201.

Harvesters should note that heat in verse 2 above is a typo. Evidently Bob Copper and Shirley Collins have understood the song differently, hence all on through happy spring (Bob) versus that long true happy Spring (Shirley) and, for that matter, Shirley's Mossom.

A midi made from the notation in Bob Copper's Songs and Southern Breezes (1973) will go in time to the Mudcat Midi Pages; in the meantime it can be heard via the South Riding Folk Network site

Banks of the Mossen (midi)