You're not going to do it on your budget sorry to tell you this, it's depressing I know and I thought I could build one on a budget and I got a lot of stuff for almost nothing including the frame and it still cost £1500

You need a vfd for the spindles they won't work without it.

I'd say neale's right £2500 is the zone I had to work real hard and had a lot of luck to get mine to £1500 some things are not worth wasting money on like those motors and drivers you linked to other things you can scrimp on get a $5 BOB for now, make your PSU, beg a cheap table to put it on. But don't cheap ass the drivers, the frame, the slides, the motors or the ballscrews as these can;t be upgraded easily without the first ones having little resale value.

Also 10mm pitch ballscrews, don't make my mistake