pierre212... i'd be a tad wary about spending this banknote... there is no record of this s/n prefix ever being used for that denomination -- did you check all the security features on that note? if you still have it, you might want to take it to a bank for verification.

(note that no such prefix has been seen at the other money-tracking sites, it doesn't exist in any of the paper money forums and the most recent Charlton catalogue suggests that it has never been used)