The 1958 cod war was between just Iceland and the UK, nothing to do with the EU and nothing to do with quotas. It was purely down to disputed territorial waters. Britain gave up its first huge concession in the 70s only just before joining the common market because it was a condition of entry by the other members who wanted a slice of the richest fishing waters in Europe.
Maritime boundaries in Europe are now pretty much agreed upon and the UK will have the final word on who fishes within it and how much they will be allowed to catch. I know it's become a cliche but that really is an example of taking back control.
If the Cornish economy booms on the back of a fishy bonanza, I'll salute you on this. I'm not holding my breath, though.
ATB