Locations of artillery units on specific dates

[Lost in Tilloy]

Hi

I'm investigating a WW1 memorial window in my Church and wondered whether anyone had details regarding the positions of the following artillery units on the dates mentioned:

157th Brigade, Royal Field Artillery: 25th July 1916. Investigating death of Lieut Robert Gilroy Bannerman. Buried Quarry Cemetery, Montauban. Son of William and Jeanie/Jane Bannerman, Dumfries.

335th Siege Battery, Royal Garrison Artillery: 31st May 1918. Investigating the death of James George Mackenzie, Gunner 183491. Buried Gwalia, West-Vlaanderen. Son of George and Agnes Mackenzie, Edinburgh.

Regards

LIT