mounted via nfs /shares
browsed via nautilus to that directory
dragged folder from nfs server onto desktop (hoping to create a link - I'm not
generally a gui user)
realised it was "moving" the folder, clicked cancel
copied the contents of what it had put on the desktop back (to ensure all files
were back where they started)
looked in folder, 99% of contents had gone (i.e. only stuff that it had
successfully moved)

this is BIG! cancelling a move should leave you in one of the following two states :
1. all data back where it started OR
2. some data where it started, rest where moving to

NOT - and this is what happened - some data where moving to and none where
moving from.