Shaddows - 4:50 pm on Feb 2, 2009 (gmt 0)

I would definately invest in a UK-based server/hosting. We did, and targetted traffic increased. Any targetting improvement will help your CTR- and I'm not the only one who thinks CTR versus [expected CTR for position] affects ranking.

If you have a mirrored site on .com, either redirect it or prevent indexing. I'd redirect.

PR dillution- if your % increase in URLs is not matched by a similar % increase in links, you will slowly be dilluted.

Actually, that might be it. Your backlink profile might be going stale if you have not acquired new links in over a year, possibly approaching 2 years.

Also, I've re-read my post and I might have come across a bit harsh. Sorry about that.