Your link to machineryhouse didn't work.
But I'm in Wellington and I bought a Sieg X3 mill from Machineryhouse. I've fitted it with a stepper-motor/ballscrew kit from Promica in Australia. I drive the motors with a Gecko540 controller using an older PC with LPT port, running Mach3 software. I have a USB jog-shuttle controller, which has made life much easier. I have a couple of Tormach quick-change tool holders and am working on a power drawbar. I'm halfway through removing the spindle motor from the mill and replacing it with a three phase motor with a SEW-Eurodrive single phase variable speed drive.
I'd be happy to discuss your plans and offer advice from what I've learned along the way.