All the myriad of house guests seem to be sleeping in this morning so I crept off to the workshop

The cooling system has been a bit of an unknown - a big lump called a Schroff RHB 3000 bolted on to the end of the cabinet, taking in warm air from the top, and blowing it out cooled at the bottom of the cabinet. Certainly lots of air flow but I wasn't convinced it was actually cooling. I had thought that the whole thing was a factory sealed item, but yesterday when showing a nephew the lathe I realised that in fact it had a totally enclosing cover that could be removed. Hence creeping away this morning to investigate.
Taking the cover off let me gain access to a termination box that among other bits houses a contactor - contactor not pulled in, cooling compressor not running! Jamming contactor armature over into the 'made' state with a screwdriver the compressor starts up, and air coming in at the top at 25C is now exiting at 14C !
The problem can only be either one of the thermostats, possibly the contactor coil, or one of the various trip devices in series with the coil, but daren't start investigating now or my absence will be noticed!
This may account for the failed X&Z axis servo as it is first in line for the cool air.
Anyway - a few pictures
a/Over View with cover removed
b/Close up of control box
c/Circuit diagram thoughtfully provided by Schroff and glued to lid of control box!