May 1942: https://www.ibiblio.org/hyperwar/UN/UK/UK-Defence-UK/img/DefenseOfUK-49.jpg I think the original Eastern Command has had South-Eastern Command split off.
Army Council Instruction 349, 15.03.1941: Re-organization of Home Commands. The following changes in the organization of commands at home, which took effect from 15th February, 1941, are notified:-- (a) Eastern Command is divided into two independent commands, viz., Eastern Command and South-Eastern Command. (b) Aldershot Command is abolished and becomes Aldershot area under the South-Eastern Command.
This map is in the US Technical Manual on British Armed Forces, which was issued in late September 1942. It's a bit blurry I know and not terribly well detailed, included for comparison to TD's link. Look's to incorporate the change to Eastern and South-eastern commands noted by Aixman. Gary
My apologies Idler, it was your link I was referencing. I did watch Minions last night, so perhaps that put TD's current avatar into my subconscious... Gary