Gwil
Brilliant find, I had hoped that a newspaper would help.
On 24 May 1915 the battalion were in support trenches near Vlamertinge having occupied them on 21st/22nd. At 2 30 am, the firing and support trenches were heavily attacked by shelling and machine gun fire, 2 officers and 12 ORs were killed and 2 officers and 70 ORS were wounded. It would be fair to assume your man was one of the 70.
More generally, if you can bear a bit of additional info, this illustrates what Jim1 inferred about normal trench routine.
When a battalion was in the line with the fairly normal four days in and three to four days in reserve, shelling, minor attacks by both sides, sniper fire, small patrols and bombing from the air was constant. The "named" battles tended to be those that were significant to the conduct of the war in some way and did produce perhaps the most casualties but, to put it fairly brutally, the killing and wounding was going on all the time. To take the beginning of June 1915 as an example when there was "nothing going on". The battalion were in the trenches from 6th to 15th. There were men killed and wounded, by shelling and sniper fire, on all but two of those days (23 in total).
maxD