Apologies, for some reason I have only read your latest response now!
I didnt get to the root as to why the backup sizes were different on the the various storage devices. I am only using bacula to backup data to my tapes now (need to use rsync for the NAS devices for reasons I wont go into in this post), so this isnt really an issue now. But thanks for all the help!
Just a couple of questions on bacula though:-
I was told that if my tape is encrypted i couldnt restore the contents of the tape (in a complete distaster recovery situation) even if I had the bacula config files, the encryption keys, and use bscan to recreate the catalog from the tape. Is this correct???
Also, do you know whether its possible to encrypt everything on the tape apart from the the catalog??? I dont think you can, but I am no bacula expert...or even a system admin so have no clue....
Thanks for all your help once again!