Thanks a lot for the suggestion man!
I did that image in fear of this anniversary update :) I usually leave this PC clean only for gaming and watch something on Netflix so I will stick with normal full backups from time to time cause I lose almost nothing important here. But it's nice to be able to restore everything as close as possible the way it was than do a clean Windows install!
I'm going to mark this one solved. The issue (tentatively confirmed by Macrium) is that the problem is down to Windows use of the VSS snapshot routine. In other words its a bug in W10.
I would have liked to continue using W10's disk imager but unfortunately this issue meant it would not restore a disk exactly. Macrium does seem to work (once you have altered the VSS option in Macrium) and so I have gone with that option.
Quote