Thanks for the reply Gavin. My initial thought was the same as you in that it was operator error at Bet fair but I was at home Wednesday afternoon so was able to test it with and without Excel attached with numerous settings changed.
Nothing made a difference so I reinstalled cymatic on Wednesday night. First thing I noticed after reinstall was that it was using 1% CPU rather than 3% that I have been used to seeing. Then I set the autopilot running on US racing that goes in play and that was fine.
Yesterday and today so far have run no problem so a reinstall did the trick.