Thanks for the quick reply, Susan.
The trouble is knowing how long to delay installing such an update, given that the problems associated with uninstalling it (if you have any) are likely to be greater than those likely to be experienced by most people if they just hide it and don't install it at all.
At the moment I have it waiting to be installed on my two machines and a few days ago it was unchecked by MS for automatic installation implying it wasn't ready.
So for laymen like me it's impossible to know what to do for the best! It reminds me just how frustrating it is having to run an OS that needs a dozen or more updates every month, any of which could be severely problematic - I'm sure the sale of anxiety medication must rise in the second week of the month!