Calculator Maintenance Engineer...C.M.E
Danny...
These beasts weren't general purpose calculators... they were made from the same sort of electromechanical switching gear that the GPO used in automatic telephony...uniselectors and so forth. Dad being a Post Office technician.... People with these skills were needed to maintain these calculating devices. It was a special deal...he joined on a Monday and was a Corporal by Friday!! Radar gave the range and elevation of the target, and the calculator converted this to the relevant map square on the plotting table, in real time. It's only in the past decade or so I found out what it was he was dealing with!