The Royal Artillery is unique in the British Army because of the emphasis they have always placed on their sub-units: known as batteries. Batteries can deploy independently, move around between regiments and even perform different roles to one another within a single regiment.
Biscot Camp was organised into 4 Batteries and a headquarters (HQ) component.
A, B, C, and D...B was later merged into A,C and D Batteries.
Download the War Diaries for D battery below.