The legal position with regard to Scottish Banknotes is as follows:
Scottish Banknotes are legal currency – i.e. they are approved by the UK Parliament. However, Scottish Bank notes are not Legal Tender, not even in Scotland. In fact, no banknote whatsoever (including Bank of England notes!) qualifies for the term 'legal tender' north of the border and the Scottish economy seems to manage without that legal protection.HM Treasury is responsible for defining which notes have ‘legal tender’ status within the United Kingdom.
The Bank of England’s website may also help to clarify what is meant by “legal tender” and how little practical meaning the phrase has in everyday transactions. https://www.bankofengland.co.uk/knowledgebank/what-is-legal-tender
It is also interesting to note that, if the strict rules governing legal tender were to be observed in a transaction, then the exact amount due would need to be tendered since no change can be demanded.
The majority of banknotes circulating in Scotland are issued by Scottish banks. Scottish notes circulate and are accepted quite freely in Scotland and, for the most part, they are also readily accepted in England & Wales, although branches of Scottish banks there may not issue them. However, you should not rely absolutely on Scottish notes being accepted outside Scotland and this is particularly true when travelling abroad. Our general advice would be not to carry large amounts of banknotes of any description and to make use of facilities such as travellers’ cheques, credit/debit cards and ATM cards for access to funds whilst abroad.
For guidelines regarding the "legal tender" status of coins please follow the link for the Royal Mint.