London to Scotland usually crosses the Lake District where most of the flat open spaces are a bit wet.....! Given the (small) chance of a ditching in a lake, river or whatever, I thought that they always did the lifejacket bit too. Possibly your route that day took you east of the Lakes (but that would put you a bit close to the North Sea....). Just guessing though so you'll have to wait for a CC Pruner to tell us!