The only thing I've found with that name is this...
Treat Day probably originated from an annual event held at New Way Farm in the late 1860s by farmer John Taylor (whose nickname for reasons lost in the mists of time was “Shammock”) This popular celebration was known locally as “Shammock’s Do” and the day consisted of the showing of prize horses, dancing to a brass band and, to enhance the festivities, the consumption of local ale brought in barrels on carts to the farm! The popularity of this event probably led the Vicar at the time, the Rev G W Wall to form a School Treat Committee and the event soon became established in the area. The whole of the Parish became involved in the festivities, with ploughing matches, horse races and many other sporting contests taking place. - See more at:
http://www.ormskirk.gb.com/ormskirk/news_list/A_Treat_for_Bickerstaffe!-50510382.htm#sthash.WBqHiXHN.dpuf