I haven't posted here throughout but wanted to let the other folks who might be wondering if it's possible to do this with a 40+ BMI - it's possible and it's not painful when you do it right.
I started walking 5 minutes per hour with a BMI of 43.5 on July 4th, was walking for an hour a day by September.
That walking alone has ended my nightly leg cramps, maybe a little thing to someone else but to me that's was an almost immediate benefit.
In September I plucked up my courage and advanced to the C25K plan then. Like the inexperienced runner I promptly injured myself in week 2 (extensor tendonitis) and was laid up for nearly a month - get good running shoes and advice on how to tie and tighten them to avoid this.
From mid-October onwards I restarted C25K and completed w9R3 on December 30th.
While I now run faster than I can walk that wasn't always the case during the plan, don't be afraid to slow right down and concentrate on doing the time. No problem taking weeks more than once either - I redid weeks 1 and 2 post injury and week 6 later on.
I'm not fast - moving (now) 23st5lb requires plenty of effort - I have improved my pace steadily over the plan. Doing 5k in the 30 minutes is still an aspiration, maybe by the end of this year
To anyone with high BMI reading this (mine is now down to 41.2) and wondering, is this for me or is it just for them? My words are simple; make it for yours!
My best to everyone on this journey now or in the future.