Update for anyone viewing this and having the same problem.
I tried to alter my mouse settings but to no avail.
My solution was, although VERY happy with Chrome, i switched to Firefox for WGT only. I found from a alternate mac forum that Chrome suffers from mouse lag. after comparing it to Firefox, it does.
I also found, for some reason, that the only flash installed seem to be imbedded in Chrome. When i tried to open firefox the first time, no flash ? So i downloaded the latest version from adobe for macs and all was well.
The magic mouse is not very good for WGT so i use a cheap gaming mouse and its a lot better.
Thanks for the tips people and i hope this reply helps a few that have the same issues,
x