The plaque above the fireplace would be quite a clue to his background. Much respect.
On close inspection this plaque show the badge of the "Scots Greys" - of Waterloo fame and hence the French eagle - which were known as the 2nd Dragoons from 1877 to 1971 and during WW2 they used horses in Palestine and ended up as an armoured regiment.
Looking at the age of the photo - if it is him - then could he be a Trooper from that unit one wonders?