Found the reference. It was Halifax, not Otley (sorry). Goes like this.

"Written by members of a Halifax church choir in 1886. The choir was on a picnic on Ilkley Moor when two of the party, a courting couple, wandered off on their own. When they returned, the choir greeted them with parody of the hymn tune Cranbrook. Other verses were added later and Mary Jane and her young man found a lasting place in Yorkshire song."

Cheers!
Ian