I have an assortment of old notes, mainly UK £1 and 10 shilling, and one of the serial numbers starts 35S as opposed to starting with letters. Is there any significance to this?
Must be more common than I thought. Mind you, they've been out of circulation for a while. Got caught out in a pub quiz lately, question was, when did pound coins replace pound notes? 1983 I said-wrong. 1988 was the answer as that was when the notes were taken out of circulation, and the coin replaced them.