I have passed on the info to my friend who is the proud owner of the Almera.
It transpires that he had a mis-fire which he cured by fitting a coil but the MIL light stayed on. He decided he could clear the code by dis-connecting the battery. I suspect he did so with the keys in the ignition - possibly with the ignition on!
Oh well! At least I could clear his mis-fire code!
If all else fails I have put him in touch with another Mate who has the Nissan Diagnostic equipment.