To second Gryph most estates like/require you to use moderators and every estate/loaner rifle I've used had a moderator. Also, they also like/prefer you to use an attached bipod or shooting sticks. It does make sense since in some places shooting an unmoderated rifle can "clear the hill" and limit opportunities for the rest of the day. As is the case in most of Europe, the straight pull Blaser rifles are pretty ubiquitous for estate rifles. While they are accurate, I'm not a fan of them... they have even less romance with a big moderator and bipod attached...

Having said that I've also brought traditional rifles with me and had no problems with using them.

For a hunt I would recommend contacting Hendry, Ramsay and Waters. I've used them on several Scottish hunts and Vernon runs a good operation. Also very accommodating for international visitors coming as single stalkers.

http://www.scothunt.co.uk/

You can see some of my past stalks with them: PM if you want more specifics http://forums.nitroexpress.com/showflat.php?Cat=0&Number=263868&an=0&page=0#Post263868