Thanks - further investigation suggests that you're coreect. The tune "Wir Pflügen (Dresden)" was apparently written by Johann Abraham Peter Schulz. Mind you that doesn't preclude it from being a 'traditional' tune that Schulz borrowed (Vaughan Williams style) Maybe I just want it to be that way...
Apologies if I've hijacked your thread. I've had a good look round but can't find the lyrics you want. If you have no luck here I'd suggest emailing Gwilym Davies email@example.com who seems to be something of an authority on Gloucestershire Songs