Not sure if this is the right place to ask this kind of thing but I figured it would be a good place to start.
For context I’ve lived in Bermuda for a while and recently a hurricane passed through and broke off some of the doors to some derelict buildings in dockyard (an old Royal Navy base). Specifically in the Victualing yard, being curios and stupid I decided to walk into one of the buildings and surprisingly it was pretty intact. On the underside of a staircase I found this painting.
These stairs lead to the second floor of the building which is heavily dilapidated on one side and has a church on the other. In my years living here I’ve never heard of anyone mentioning these buildings being used as a church so this situation is strange all around. I’ve been googling these ranks and location for the past few days and have yet to find a definitive answer. I’m almost positive it’s military but I’m not sure if it’s English or American, or if it’s a religious thing which could be entirely different. The dates range from the 1950s to the 1960’s. During this time frame I believe the base would still have had military personnel active on it. If anyone needs clarification let me know!
As you surmise, the abbreviations on the board you've photographed refer to ranks within the Royal Navy or the Royal Marines, as follows:
C.E.R.A. - Chief Engine Room Artificer (a senior non-commissioned rank in the RN - the man in minute-by-minute charge of the engine room or any other complex system)
L/S and L/Sea - Lance sergeant, a non-substantive rank in the Royal Marines; basically, a lance corporal acting as a sergeant
L.M.E. - Leading Marine Engineer
M.E. - Marine Engineer
M.E.I. - Marine Engineer Instructor