I forgot to mention, when they are stored on the FTP they are not named, they have either a 6 or 8 digit (I can't remember) unique name BFM assigns to all their games. With the S2 ones I had a document which told me which number related to which game, and I made an effort with the S2's to rename all the files appropriately. I may have done it for a few early S4 dumps, but I honestly cannot remember, it's likely I stored them as found with the numerical name.
And just to make things more interesting, I am not sure if I ever saved the document which could decode them to the back up drive
Should still be possible to work out what is what by loading them into the EMU, but I doubt thats something I could be bothered with right now.