I have it on an LP sung by Ewan MacColl and Peggy Seeger ('Freeborn man', released 1983) as 'North Sea Holes' both on the record cover and on the record itself.

The renaming must have come later and by other people than MacColl. Just to be sure I have listened to a midi of one of the 'North sea shoals' titled tracks. It is the same song.

The tracklist of the rerelease of the original Singing the fishing Radio ballad doesn't help for it only gives the first lines. North sea holes is distributed on several tracks (2, 6, ...)

The Corries are not consistent: On this Corries discography it says:

BONNET, BELT AND SWORD (1967)            Philips/Phonogram (822 084-1)
                                        Fontana/Phonogram STL 5401
                Also Philips Priceless series PRIMC 67 (822 084-4), with
                title mistakenly given as "Belt, Buckle and Sword"
(Studio recording)
...
North Sea Shoals       (Cassette release has "North Sea Holes" as title)

The Google-test finds 800 odd "North sea holes" and 80 odd "North sea shoals".

Wolfgang