The instructions are quite specific about repartitioning, i.e. dont do it and I wasn't sure if mine had been altered by Shirtpocket. Having looked more closely I can see that they haven't the other thing that was throwing was my 4Gb was sitting on /dev/hdd, and I'm pretty sure the OZ installer script writes to /dev/hda. I've resolved that by remembering to take out the SD card!
Are english Sharp ROMS easily available? How feasible is it then for me to backup what my current install so that I can revert back to it if needed?