Royal Artillery at Mersea.
Thought to be 373 Coast Defence Battery, who were at West Mersea from July 1940.
Front row L-R 6. is Sgt. Major Harry [ Henry ] Conway - David Conway's father. He settled on the island and was a bus driver in later years.
7. U/O Charlton, 8. Capt. Mitchell, 9. 2/Lt Durrell.
Third row from front, L-R, 8. is thought to be Gnr. Noel Beadle - from Chris Harris, who goes on to say "I think that this picture is actually from 1940 (or earlier) as Noel was a L/bdr in January 1941 and in the photo he is clearly not in the front two rows where we find the Officers and NCO's.
It was probably taken when the Battery was first set up.
I have zoomed in on the officers to see if their ranks are visible.
Central is Capt. Mitchell. One would normally expect his junior officer next and the BSM on his right but I think looking at their epaulets, the taller younger one is Charlton without any pips, wearing a civvy shirt. Has he not yet received full issue of uniform ?"
There are other Mersea names who could be in this picture:
Gunner Charles Simmonds, who married Joan Woolf
Gunner Henry Bruce who married Alison Menzies
Sergeant Frederick Barton who married Lillian Hempstead
Corporal Ronald Swiggs who married Gladys Green