I wouldn't expect Spanish fishermen to chose a sudden cessation of being able to fish British waters to a longer (3 years, 5 years, 10 years?) period of fishing UK waters in which to plan for their future fishing areas.

Nor would I. But that is precisely what gets us back to how does this benefit the UK fishing industry. The Spanish still have the licence to fish. I, were I a UK fishing fleet owner, still have what I have now, or have perhaps had it extended to the maximum my existing fleet can cope with, but should I invest in new boats knowing that when the Spanish licence comes to an end there is no guarantee the Spanish will not win the next round, so all my investment is wasted?

Unlike many Brexit issues, I think this one is actually soluable, but only if 'getting back control' means the UK will actively control it rather than just letting the market decide. It will have to refuse some profitable licences to help UK industry. Totally against what Longworth says we need to do to get the Brexit benefit, but hey ho!