Firstly my thanks go to Sampson63 you have made me feel a lot better knowing it's not just me affected, and I very much appreciate the help given by DavidR who always seems to be around when members technical problems occur.
I have also tried the suggestions, but each one simply allows the different Avast ball to continue, but like Sampson63 I'm not too bothered as it's only a very small visual difference.
Regards Bizet.