From reading the manual it was my understanding that when importing multiple samples from CF, the initial motions of assigning the first sample to the first pad in a bank (in my case, bank C) would be followed by assignment of the subsequent samples to the subsequent pads/banks, in order of filename.

The first 12 samples are automatically assigned to bank C, as expected. Great! However, the import stops there and the subsequent banks/pads remain empty.

How do I ensure that the sample assignment continues throughout the remaining banks? I tried choosing the next bank and repeating the import process, but this just imports the first 12 samples again.

I intend to give the manual another good trawling when I get home from work I think, but if anyone can point me in the right direction it would be most appreciated.

It should do it like you said...
Just make sure that all files are in the correct format... The machine stops loading cause of some kinda unreadable file sort. I guess that's it.

I thought that might be the reason at first, but it's worth noting that the next few files to be imported (after the first 12) are from the same source as those immediately preceding it (which imported without issue)!

Additionally, there is no error on the display to reflect a problem with the import. I was getting such an error on my first attempted import (when some 808 samples were not of a suitable format), but when these were removed from the card the whole C bank filled up nicely.

I just find it odd that it stops at the end of C bank. It's either a weird coincidence, or there's something else I'm missing...

check the filez anyway. Try to import only the ones that won't load after the 12 ones... oh and I guess there is sth about the names of the files. You know like those $&%!#+ and so on. I guess they are forbidden to use.
Just try to rename your files. . .

The file naming conventions aren't the problem, I took that into account

I'll try your other suggestion. Thanks very much!