Royal Air Force, the RAF eagle is the flash at the top of the sleeves.
Rank - at least a sergeant, there are marks or creases above the chevrons, not a chief technician by angle of marks but could be a flight sergeant.
Not air crew. No lapel badges so not medical or dental. No trade flashes on arm so excludes several trades.
Could have worked on aircraft or office/stores etc. Can only excludes certain trades but can't say exactly what he did.
