You could change the DNS records associated with the www.scotroad.co.uk
domain to point them directly to the site where it is hosted now.
Alternatively, you could compy the entire site to be hosted on PN servers as well. (And have two copies of the same site - but this way you'd have to upload changes to both hosts each time you made a change)
Or move the content to PN's hosting, and get rid of the old copy. (You could put an auto-redirect page there to inform people the site has moved, and to re-direct them automaticaly after a time)
I suppose the question really is what would be the most ideal solution for you - then somebody can go into detailed steps to acheive the desired result.