Hi Pete,
moving stuff on the same drive is always that - a new pointer to an existing file (this can also be the tombstone) in the MFT is written, that's it.
But I can smell potential problems doing so, since moving the pointers does indeed not move the real files in DE\Shares on the other disks, so if later the disk needs to be managed by drive extender, i.e. to move duplicated files or to empty a disk for replacement
the shares as Windows sees them and the pointers do not match. (At least you will be confused, if you have to recover stuff manually, because it is in a different location than expected.)
Again the strong hint: Never touch D:\shares manually! As usual the only supported way is indeed moving via UNC path.
Best greetings from Germany
Olaf