Thanks for the welcome. I've spent the last few days stripping and looking at ebay for bits.
I've already got 12Nm Stepper Motor and Driver but I need to get two 3.1 Nm Stepper Motors and Drivers. I also need to buy some ballscrews and nuts.
I've not decided what to do about controlling the mill; linuxcnc or Mach3 software? I like the look of the Linux but I've not dabbled with it before. I'm also slightly tempted to use my Raspberry Pi.
Many things to think about.

Any advice welcome!