Many years ago, I'd guess in the early 1990s, for several years in a row, the Milk Race started at Land's End. The warden of LE YHA, Brian Wood, was a keen audaxer and organised a program of audaxes over the weekend (usually a BH), and it was planned so that you could watch the racing and ride your bike round Cornwall, and then follow the race as it left the SW (often into S Wales where I lived at the time). I was a regular there.
One year I was driving there, still a long way from the SW, when I was overtaken by about half a dozen motorcycles. They were all police motorbikes, but the livery was all subtly different, and the insignia showed different forces. Some time later I realised that they were also heading for the start of the Milk Race.