Thanks guys, I'll have a bit of a search around and see what I can dig up.

I'm not totally gutted as at £50 am sure I can sell on the ballscrews I have at a profit anyway, should I never find a use for them :)

I'm thinking to aim for a working area around a4 sized, very likely the first build will be MDF as I don't have much in the way of metal tools.

What sort of size ballscrew will be most suitable? Is it as simple as the lower mass ballscrew/nut, the smaller motor or faster acceleration/deceleration can be achieved, for any given motor?