If you look at the Wikipedia page for HATN you see a sign saying "THE NORTH Hatfield A1(M)". This is the standard for road signs after the Worboys review of 1965 - an area of the UK would always proceed a place name. So for a road sign to have said "Hatfield And The North" it would have to date from before Worboys. Unfortunately very few such signs still exist and the main roads were upgraded first. So unlikely there would still have been pre-Warboys signs on the A1 in 1972 when HATN were formed.
No less an authority (or geek depending on your point of view) than Chris Marshall of CBRD agrees with me the sign probably never existed with that wording. The old signs did not tend to give long distance destinations.
I really ought to put this on to the talk page on Wikipedia...
