A certain amount of fuss is always made in the media about cash ceasing to be 'legal tender'.
The truth is that all that legal tender means is that it defines what must
be accepted if offered in payment of a debt. Other than that it has no practical significance at all. And as it happens, as far as Scotland is concerned, bank notes have never been legal tender, not even Scottish ones. And yet people have no trouble spending bank notes in Scotland. Ditto for NI.
If you try and spend an old tenner in a shop, it's up to them whether or not they will accept it. The big banks will continue to accept them for years to come. I recall a chap from Nat West on the telly recently, saying that they were still processing a few million quids worth of pre-decimalisation currency every year. (Decimalisation was in 1971!)
Or you all can read this.
http://edu.bankofengland.co.uk/knowledg ... al-tender/