Thank you so much David for your help. Yes, when I clicked “change” the Avast screen came up and “repair” was on it. I clicked “repair” and it went through like a dream. Seems all OK and fully updated. We will see now if it automatically updates. I have checked the “enable streaming updates”.
Is this a multi option single button (as used in old OS versions) ?
Using/selecting the Change option will display another window that should have Repair on that.