Have a look at: http://www.mountainbikescotland.com/. This is run by a gentleman called Kenny Wilson who is a superb guy and has written a very good book.
Here is a link to Kenny's book.
The url for the site you have found seems a bit close to Kenny's, a little bit cheeky if you ask me… Perhaps not so cheeky if it is the Andy mentioned above!
If your coming up to scotland what kind of riding are you looking for? The trail centers are superb and I can put you in touch with someone that does guided routes from his bike shop of some great natural stuff as well… 😀