I am trying to restore an iTunes backup of my daughter's iPhone SE that was made via iTunes on a Mac.
The Mac runs macOS 10.14.1 and iPhone is running iOS 12.1
When I click "Restore Backup" it starts a progress bar, counts down for about five minutes and then says "Not enough space on iPhone".
This seems bizarre to me - surely the backup is some sort of snapshot of the contents of the exact same phone, so how can it now be too large to fit back into the phone?
Apple Support simply suggest Restore iPhone (i.e. erase everything) and hope that the backup works then - obviously since the backup has already failed, I am reluctant to double down on it.
Is there any way to find out how much extra space is actually needed?