Geoff,
That's an awesome bit of kit even if the box is rubbish.
I think you would be struggling to build one for that price given it comes with high speed spindle and VFD ?

I have a Teckno-Isel router but it's only 300 x 300 working area and this looks to fit the bill ideally.

I'd be interested to see how accurate this is when you have it running.