Thanks for the MCB advice. Will try 6A type D to start with.
After a little more reading, going to go for a 500va 230v primary, 2x 30v secondary. This should give me nominal 60vac when wired in series, and max voltage of 69vac when considering the mains can vary +10%, and transformer output by +6%.
A 2 x35 would give max of 81vac which is above the driver max of 80vac.

What's the recommended connectors for the high voltage wires from the PSU to the drivers?