Boris Johnson (world-renowned statesman and party animal) is on record as saying "we had a referendum [on Europe] in 1975 and we then had another one in 2016. That seems to be about the right sort of gap." Johnson was talking in the context of reiterating his position that a Scottish independence referendum should be a "once-in-a-generation" vote:
https://www.bbc.co.uk/news/uk-scotland-scotland-politics-55521732
I suppose it's just possible that he could be wrong, and that the Scottish deserve another vote on independence before I'm asked (yet again) to vote on EU membership - consistent with Ray's timescale rather than Neil's. I wonder how an independent Scotland's relationship with the EU would affect "us". Or the nationality of fish, for that matter.