The way I understand it is CTM had a hip (or knee) replacement and as part if his recovery needed to exercise it was suggested by a member of the family he could do 100 laps of the garden in the £million plus home they all lived in. One daughter happens to be in PR. Local news alerted, then national, then international, crazy pandemic times so brass bands, book deal, Michael Ball, knighthood etc.
At the same time there were lots of other people doing amazing things to raise money for covid. Without googling I think I remember a kid sleeping in a tent for months and a child with horrific injuries from early life abuse walking a significant number of miles on false legs.
Unfortunately they did not have the Hannah Ingrham-Moore PR machine.
As for the 'war hero', like most families of a similar age I have grand-parents, great uncles who fought in the war, not all came home. My late mother-in-law escaped now Yangon walking through the Darjeeling jungle and then lied about her age at 14 to join the war effort.
CTM was a very comfortably off old man walking around his garden. The fact it became an international fund raising event is down to his daughter, and if she left it there, fair enough. Without considering 'The Foundation', the fame and recognition she continues to crave is embarrassing. For example, Wimbledon.