Hi Ken,

thanks for that, should have thought of checking that myself! I've just opened an old backup of the project which worked fine, and that ran at normal speed. Then I went back to the current version, opened that, and that now also runs fine! How strange. I had restarted the computer a few times before which didn't fix it, so I'm suprised it's working fine again now, but no complaints now it's working!

 All is working now by the looks of it so thanks very much for your help.

Phil.