//Isn’t it strange (some may even say ironic) that to regain sovereignty we had to exercise our parliamentary sovereignty, thereby proving we still had it all along!//
Nothing ironic, Zacs. The only aspect of our sovereignty we could exercise without permission was to leave. Virtually every other aspect of Parliamentary sovereignty that the UK might exercise was subject to scrutiny and possible veto by the Euromaniacs.
I see no reason why the UK should not defend its fishing grounds as it sees fit. No doubt an accommodation might have been reached over them had the EU accepted that they were ours to control. But they didn't. They still behaved as if we were supplicants and that they would decide how much of our own resources we would be allowed to retain. A small part of the price for access to the "Single Market" (aka the European Protection Racket) was to forfeit the right to those resources. No other nation would negotiate a trade deal on that basis.