1. He was Welsh by birth and spent the early years of his short life in Barry, South Wales.
The documentation relevant here are the War Diary of the 106th Brigade and the personal diary of the officer commanding the 106th Brigade at the time, Lieutenant Colonel Ralph G.A. Hamilton, Master of Belhaven. I've quoted them both below as they are worth reading. The Brigade War Diary entries are brief but do mention that D Battery was hit by a gas shell on June 4th, with nine casualties, one of whom would have been William Conibear. The personal diary of Lieutenant Colonel Hamilton's is far more expansive and paints a vivid picture of life at the front at that particular time and what men such as William had to endure. William was buried very close to where he died, in the Railway Dugouts War Cemetery.
From the 106th Brigade, Royal Field Artillery War Diary for June 1917:
Friday June 1st: Batteries wire cutting on Mt Sorrel zone. (meaning firing barrages to destroy enemy barb wire defences).
Saturday June 2nd: Ditto. Batteries also fire in support of small raid on Spoil Bank Sector.
Sunday June 3rd: Practice barrage at 3.15pm. Batteries wire cutting.
Monday June 4th: Brigade Commanders Conference at Busseboom. 2.30 pm. Railway Dugouts shelled with gas shell. D (Battery)/106 shelled 9 casualties. Total Brigade casualties for first week 34.
From Lieutenant Colonel Hamilton’s Personal Diary: