The A1 might have had a prodigious title in those days, The Great North Road, but it scarcely lived up to it save for the amount of traffic, particularly commercial, that it carried on its many single carriageway sections.
Four fellow Cranwell cadets, crammed into a Mini, were lucky to survive a head-on collision with a British Road Services lorry in the Stamford area. Those in the front were saved by the full harness Irving safety belts (a rare innovation back then), while those in the rear were at least restrained by the front seat backs not folding up with their occupants. As it was the engine moved aft into the passenger cabin. The upshot was a loss of aircrew status for at least one of them, but it could have been so much worse...
The Minor's party piece that you describe, Danny, must have greatly alarmed its occupants, but in its favour I would like to say that it was at least the overtaking vehicle in that case. How many of us have been stuck in a line of vehicles behind one, maintaining a steady 30mph on a clear unrestricted single carriageway road? Perhaps though it is a measure of the appeal the marque has to those who would do all their motoring at 30mph or less rather than of the car itself. If #2 is also of a similar disposition you are doomed to convoy with them until they finally go their separate ways. Better that than to try the desperate manoeuvre that you so vividly describe!