As ever brilliant information from David Porter

For the benefit of others this is my current crib sheet - i.e. not 100% accurate with some based on guesswork.

No. 1 Depot RFA (1 Reserve Brigade) at Newcastle-on-Tyne

1A Reserve Brigade consisting of 1, 2 and 3 Batteries. Newcastle upon Tyne (55 Battery added)

1B Reserve Brigade consisting of 4, 5 and 6 Batteries. Forest Row (initially Leeds then Ipswich in March 1916)

No. 2 Depot RFA (2 Reserve Brigade) at Preston

2A Reserve Brigade consisting of 7, 8 and 9 Batteries. Preston

2B Reserve Brigade consisting of 10, 11 and 12 Batteries. Brighton (also No. 4 RFA Officer Cadets School)

No. 3 Depot RFA (3 Reserve Brigade) at Hilsea, Cosham Railway Station

3A Reserve Brigade consisting of 13, 14 and 15 Batteries. Larkhill (57 Battery added)

3B Reserve Brigade consisting of 16, 17 and 18 Batteries. Topsham Barracks, Exeter (also No. 2 RFA Officer Cadet School)

No. 4 Depot RFA (4 Reserve Brigade) at Woolwich

4A Reserve Brigade consisting of 19, 20 and 21 Batteries. Woolwich (56 Battery replaced 20)

4B Reserve Brigade consisting of 22, 23 and 24 Batteries. Boyton, Wilts

No. 5 Depot RFA (5 Reserve Brigade) at Athlone

5A Reserve Brigade consisting of 25, 26 and 27 Batteries. Athlone

5B Reserve Brigade (28, 29 and 30 Batteries ??) broken up ??

No. 6 Depot RFA (6 Reserve Brigade) at Glasgow, Maryhill Barracks (possibly Edinburgh in 1918)

6A Reserve Brigade (31, 32, and 33 Batteries ??) broken up ?? - 31st Reserve Battery remount training unit. Glasgow

6B Reserve Brigade consisting of 34, 35 and 36 Batteries. Piershill Barracks, Edinburgh

No. 7 Depot RFA (7 Reserve Brigade) at Romsey

Added later

1C Reserve Brigade consisted of 37, 38 and 39 Batteries. Hemel Hempstead - 37th Reserve Battery remount training unit. Northampton

2C Reserve Brigade consisting of 40, 41 and 42 Batteries. Catterick - 40th Reserve Battery remount training unit. No.8 Camp, Bulford

3C Reserve Brigade consisting of 43, 44 and 45 Batteries. Deepcut - 43rd Reserve Battery at Swanage in 1917 & 1918

4C Reserve Brigade consisting of 46, 47 and 48 Batteries. Weedon

5C Reserve Brigade consisting of 49, 50 and 51 Batteries. Charlton Park - 49th Reserve (Ballincollig) Battery

6C Reserve Brigade consisting of 52, 53.and 54 Batteries. Maryhill Barracks, Glasgow, or Redford Barracks, Edinburgh - 146 and 147 Batteries replaced 53 and 54

new 6C Reserve Brigade consisting of 53, 54.and 55 Batteries, Waterloo Barracks, Aldershot (relocated from Glasgow, Edinburgh & Newcastle ??)

new 5B Reserve Brigade consisting of 59, 60 and 61 Batteries. Edinburgh (58 Battery missing !!) (50, 59 and 60 Batteries moved to Lessness Park Camp in 1918)

62nd Reserve Battery remount training unit. Ripon

63rd Reserve Battery remount training unit. Bulford

Source: 1915/16: Reserve Batteries, RH & RFA