Ah thanks, David! I don't remember a florin and wasn't sure if 5p/a bob was the only almost identical coin. That's the mythical one like 'a half crown' in my head - I sort of know the name of the coin but have no idea what it was worth or what it looked like! Developing some sort of way of categorising these timeslips, like we can see on this thread, would be helpful now to anyone interviewing someone who had experienced one, because it would help approach this with a bit more rigour. The coinage thing strikes me as an interesting example because the shilling/5p detail would be self evident in 1973, but might be lost to us now. But the devil is probably in the details with all these things, really.