John was quicker than I am. I, too, think it was the Somme but do not have any details of the Battalion's involvement. In my researches in the PRO at Kew, I was told that quite a lot of Battalion war-diaries have survived, so you might strike lucky. Was your man "just" a private soldier or had he been promoted? The higher up the scale, the more likely that he was mentioned in the diaries. Do you know if he was awarded any medals?
(Researching Agnew, Aylmer, Boyde, Callister, Comaish, Crellin,
Cretney, Gelling & Kelly).