Look at https://en.wikipedia.org/wiki/New_Year#Annunciation_Style :

“Despite the unification of the Scottish and English royal crowns with the accession of King James VI and I in 1603, and even the union of the kingdoms themselves in 1707, England continued to use Annunciation Style while Scotland used Modern Style. This led to the act being recorded at the time in England as 6 March 1706 (rather than 1707), because in England (unlike Scotland) it fell before the new year began (on 25 March).”

It apparently caused trouble for travelers (from the New Style Calendar Act https://en.wikisource.org/wiki/Calendar_(New_Style)_Act_1750 ):

“WHEREAS the legal Supputation of the Year of our Lord in that Part of Great Britain called England, according to which the Year beginneth on the 25th Day of March, hath been found by Experience to be attended with divers Inconveniencies, not only as it differs from the Usage of neighbouring Nations, but also from the legal Method of Computation in that Part of Great Britain called Scotlond, and from the common Usage throughout the whole Kingdom, and thereby frequent Mistakes are occasioned in the Dates of Deeds, and other Writings, and Disputes arise therefrom.”

Although, I think “common usage” in that statement implies that it was common to just do what other countries did, except when filling out legal documents.