A good quality but cheap 48v 30A+ power supply ideal for CNC

[Jonathan]

That won't be an issue with these power supplies - if it was then it's quite easily mitigated anyway.

I've got hold of a Axminster (Sieg) X2 which has ballscrews on the X & Y axes already, plus a set of drives and motors

This one I presume? The motors look like the common 3Nm ones, in which case they would run faster on 75V, but you're limited to 48V by the m542 drivers so that's not an option without replacing the drivers and power supply. Should you decide that that's worthwhile, my offer still stands. Edit: Also, take the handles of when you use it as CNC, otherwise their inertia will significantly limit the acceleration you can get.

Do you know if the output of the power supply you have is isolated? If not could you do me a favour and check it? Given the intended application, I suspect they are, but would like to be sure...The manual doesn't say.