Itunes Media Folder on NAS - not sorting & storing TV Shows into seasons

Have been frantically searching through several forums for an answer on this but I'm stumped...

I've recently swapped my NAS (MyCloudMirror for a MyCloudPR2100), and I use this to store my itunes media. Library is stored on my imac. With the files on Mycloudmirror, iTunes storedeverything fine - each movie was in its own folder under /Movies (i.e. Movies/Avatar/Avatar.mpg) and each TV show had a sub folder for each season with all episodes stored by season (e.g. Friends/Season1/episode1.mpg).

I've copied the entire media library to my new Mycloudpr2100 (SSH/Rsync) so all meta data etc looks to be fine. BUT, when I re-point my library to the new media location, itunes re-sorts the files and its moving all tv episodes (regardless of season) into one TV show folder (i.e. Friends/*episodes 1-100). All movies are now under "/Movies/" rather than /Movies/Movie name sub-folder/movie.mpg. iTunes media folder isn't at root level on the NAS, and the NAS is mounted okay using AFP (just like the previous NAS). I'm thinking its access rights to the NAS but I can't figure it out - and can't find any threads with an answer that works for me - unchecking/rechecking the sort files/consolidate doesn't work.

Any ideas please?