In 1666 King Charles II granted 50 fishermen from the city of Bruges ‘eternal access’ to British waters, and the EU are now trying to 'grandfather' this treaty. Is this treaty valid under all possible circumstances, or is it possible to claim that this is no longer appropriate to present day circumstances? And moreover, is it possible for the entire EU to inherit the treaty in the first place without any questions being asked, given that the EU is not the 'Enlarged Country of Belgium (or any other member state)'.
This is a somewhat analagous situation to a new-build Housing Estate in a rural area. While planning permission may have been granted for the houses, the land itself is subject to an ancient historical 'Covenant' which was drawn up hundreds of years before work started on the Housing site. Theoretically speaking the Covenant applies for all time, but it is possible to make an application to 'discharge' the Covenant on the grounds that it is no longer appropriate to the present day use of the land, even if it can be very expensive to do so in practise.
Is it possible to pursue an analagous process for the seas?