Following up your other query, I think McNasty completed the full series of ‘roughly 200km’ brevets around the British coast as a consecutive series but with rest days. https://yacf.co.uk/forum/index.php?topic=79021.0
Yes. I think that Mc Nasty might have been the only one who rode the whole route. If it's what I think it might be, then it was part of a chain of events that started around the early-mid 90s when I got stuck into points chasing.
My chronology might be off and I've probably missed things out, but going from the beginning.
1st, there were Calendar events
Then there were perms
Pete Coulson set up the Lincoln-Winchester perms (so Liz Creese could ride the same route without falling foul of the now obsolete, no repeated rides for championship award rule)
This is where I came in, so around 1994.
Sheila Simpson set up Hostel Arrows, that were loosely based on Easter Arrows (so the French Fleche rides) You basically had 24 hours to do 360km-720km and must either start or finish at a YHA youth hostel (because they all had stamps in those days and this was before we collected receipts, which followed just a few years later as rubber stamps diminished from everywhere and till receipts became more high tech)
Alongside the Hostel Arrows, were Hostel Darts. Same thing, only 12 hours instead of 24. Same max/min speed.
Next was Pete Coulson's Round the Coast series of 200km rides.
It was around that time that Bernard Mawson also set an almost identical series of rides around the coast!
I don't know much about Bernard Mawson's events. Pete Coulson was local, so I rode his events and didn't take much notice of Bernard's.
But Pete also set up coastal darts (and arrows too IIRC) so that you could ride a perm to the start of one of his rides around the coast. They were based on Sheila's Hostel Darts and Arrows (which were based on Easter Arrows etc)
I expect that Bernard Mawson did the same for his coastal rides, which may be the brevet card that you have.
Then came the Midlands Mesh which almost killed everything off until the DIY killed that off. The YHA closing hostel didn't help with the Hostel Arrow and Darts, which died in the early 2000s. A same, I had some very nice rides that ended with me staying in a hostel. I used them as a way of riding to and from events and claiming points when I was points chasing back then.