You're very welcome kind sir. I wasn't sure whether you were in the Forest (power of tinternet etc) but if you are in the area then I suspect it's your best bet. I certainly super-Googled this rather interesting subject last night to little avail...

Re the Mercury archives pls see my recent post

http://www.forum.forest-of-dean.net/index.php?id=34114

If you search the Forum you'll find other similar posts.

Happy hunting !