Take sterling, clean and crisp and not Scottish notes. Only exchange at the hotels and not at change booths, ideally take some cash and then a cash card. There are two cash machines, one at the Gondola and one behind the buzz bar and the exchange rate will probably be better than at the hotel . You should get charged £1.50 for the transaction by your bank.
We took Levs into Bulgaria last year. Hope I didn't break any laws! Changed up enough for the first couple of days at Thomas Crook, because our flight was moved to a red eye.