Oil currently not worth much, has been nothing. In the future will be worth nothing. Whiskey is a billion pound industry. But London is a 2000 billion pound finance industry.
Scotland is not subsidising anyone. Just because oil is in the North Sea doesn't make it Scottish. It doesn't come out in tartan patterns. If they pay for it's extraction, infrastructure, transport and refinery and pay for the navy to protect it, then they can have it. After those expenses oil is a massive loss with no future. And whiskey isn't going to expand in a more and more tee total world. Scottish Independence would likely bankrupt Scotland, unless subsidised heavily. Which it already is.

Red and Blue Army!