What I would do
1 Batter the canvassing area within walking distance of your home - no need for transport to start with.
2 Forget wfp for now - water too heavy to lug around plus with your dodgy ticker ...........................
3 Learn trad
4 Trad the upstairs with a pole and wagtail - see waggas you tube videos to see how its done .... if you make a few mistakes so what just a means to an end.
5 Save pennies for a motor
Gerald this advice is probably the best here.
I know it may seem like there's no real way to get started, but this advice from Ian can work.
£50 a day should be easily achievable within walking distance from your home.
As tosh says though, keep your health (mentally and physically) as top priority and the rest will follow.
I agree 100% with both the above.
There's someone who cycles around Brighton with a small trailer and does downstairs trad and upstairs with a pole and he seems to have no problems getting the work.
There's also someone else who has adapted a shopping trolley (the type that old biddies push to the shops and back) which although it looks hysterical, it also very functional. He does it all trad, walks from job to job and does upstairs with a pole.
The good thing about working like that, no overheads worth speaking of and almost 100% profit.