Now I don't like autotransformers at the best of times, as they offer no isolation, and that number of tappings is silly

Going through the Bosch manual for the drive, what it needs is two 180 volt windings aranged 180-0-180, and a further 200 volt winding added to one of the 180's to give 380 volts. The main power is taken by the 180 volt windings, and the 380 volts uses a measly 10 VA, and feeds an internal transformer generating 15-0-15 volts DC and also it uses this winding to get the synchronisation of the thyristor drives.
Searching around there were no suitable transformers 'off the shelf' or available second hand, so I'm having one wound. But what power? Well in a Bridgeport Interact it would feed three axis's and potentially a 4th axis rotary drive, and was 3 kW. Pro-rata that means that my 4th axis only needs 750 VA, and I reckon that's probably over stating it as the main axis drives will take more than the 4th axis.
I've simplified the secondaries to just the three needed ones, but have added a 415 v primary for isolation, with a 240 volt tapping so I can drive it off mains on the bench for testing. I upped the 200 volt winding to 50 VA so that they don't use stupidly thin wire.
As a 1 kVA transformer was not much more than a 750 VA that's what I plumped for: