Thank you Flash.
All I did was comment out the line
i.e. #ScanPartialMessages false
Then I tried to check the version again and recived an error about
HeuristicScanPrecedence so I commented that out as well
i.e. #HeuristicScanPrecedence false
Then for good measure I commented out the last one
now no more error messages, and speed has returned.
After commenting out the lines, I was able to find version of clamav. It is:
I realise that the latest is 0.95 but after what I have been through with upgrades, I am going to give this a miss for now.
I am happy to have my mail seerver back to functional.
Thank you for your help Flash.