Hello
Thank you to everyone who replied.
Ideally I would have liked to continue to use the Coordinate Menu Widget as it had all the functionality I wanted, but as it does not go beyond version 3.3 this was not a viable option.
I have instead used the Enhanced Locate widget and disabled the extra views to just leave the zoom to xy screen. This works great.
In terms of getting the xy coordinates in the first place my users will have to get used to hovering the mouse over the point they want and noting down the coordinates that appear in the bottom left of the screen.
Thanks again for all the replies
Emma