Remember, there already was a referendum and while full independence almost got its show, the majority still voted to remain in the UK, but mainly for the security of the single market within EU. Visited the highlands and was painfully obvious (or deliberately made to look obvious) how much Scotland relied on EU funding to restore buildings, maintain those remote islands, crops, farming, etc.
The mention of a currency change screwed them last time if I remember rightly. And it will again. They should make no mention of it other than vague plans. People do not like having the certainty of their money thrown up in the air. They care about that far above and beyond any politics.
It reminds me of my local MP who came out as anti hunt just before her re election in an area that's rabidly pro hunt. Funnily enough she lost.