I think you will actually find that most Macmillan nurses, are actually funded by the NHS, the charity only funds them for a few years. And all they are really doing, is leeching nurses from the general scope of the NHS (though they are still employed by the NHS) and putting them into a specialist role whilst paying them a higher wage - they are merely doing the job they are getting paid to do, so why are they special??
Btw, as a former 100m/200m sprinter and cross country runner for Wirral at junior levelfrom the age of about 7 (until I had my second heart operation at 14), a marathon isnt something that you just decide to do on the spare of the moment, you need to specifically train and prepare both physically and mentally for it. Most people, even if you think you are relatively fit, will feel like dying and give up after 3 - 5 miles, nevermind 26 miles. I did consider taking up running again ater a few years of laziness and of course a not-so-healthy lifestyle, when I was 18/19 and used to run from Thurstaston to West Kirby and back (along the Wirral Way) 3 mornings a week, thats about 6 miles in total give or take and even I found it a challenge.