The "boxed" version for the £199.00 is just the item as it comes from china in it's shipping crate. The additional £75.00 was for the machine to be degreased and stripped down and then reasembled and adjusted. I assume they must come with some kind of gloop applied to the bare metal surfaces to prevent corrusion during storage which you have to clear off prior to use.
The part that bothered me a bit was this site:
http://myweb.tiscali.co.uk/silkstone...inilathe01.htm
There seemed to be a lot of adjustments required, shimming etc and a lot of modifications to the Tailstock.
I guess it's like anything you buy, a bicycle from the shop will need to be dissasembled and adjusted prior to riding it, even though it is supposedly setup in the shop.