@ Mozzerfan & MBrantley,
Cheers guys for the help. I played a quick game of Star Trek Amarda, calmed down, fed the dog and went back to the Miggy.
In short, I've got it reading my memory stick!!! Yeah!!! OK, I officially love this thing - Deneb rocks! :-)
I think the problem with the MUI install was that I used WinRAR to extract it, copied the files to 2 floppy disks, dumped them in a single folder on DH0: and tried installing from theere. Something ebcame broke in the process.
I downloaded LHA and copied that to my C: folder, copied the MUI LHA archive from the floppy to the HD, extracted it via the command "LHA x DH0:38USR.LHA" to the RAM: drive and installed it from there.
I could then access Poseidon preferences. I then rebooted, went back into the prefs, cleared all the error messages in the log, shoved the USB stick back in and then watched Poseidon mount it in seconds!
Next I need to get brave, dig out my old USB CD ROM drive and then see if I can use that instead of the ****ing IDE one.
Can I just suggest, for ease of use, that the following files are added to the Flash ROM for future Deneb batches:
Latest INSTALLER file.
MUI install package.
I need to test that USB to SATA/IDE cable again too...