Dave CCleaner: Applications show both Office 2013 and Office 2016, both are unticked. However, I suspect that you are right it is the Start Menu and Desktop shortcuts that are disappearing which means that I have to re-install to get them back. Whether it is actually CCleaner which is the cause or not, I cannot prove. The EasyClean doesn't have this effect, just the Custom Clean.
Thanks to all for your replies and help.