Nice machine, I would consider one myself if I was looking in that size range. I don't think it is necessarily out of stepper territory though.
As for supplies of screws etc, UK sourced is going to cost you big time. I wouldn't bother, hit Ebay or one of the US vendors. Even with the current exchange rate you'll probably save money. I got a load of stuff from homeshopcnc.com and was very happy with it. Plus its pretty much a 1-stop shop.