Running

Sparky, there's a load of hyper-negative nonsense being spouted around here. If you've run 15 miles, you can easily run a marathon. If you go along with the 'only go up by 10% a week' school of thought, it will take you 8 years to progress to a marathon from a 5km. Or so. One long run a week and a bunch of shorter ones will see you right. Maybe leave the 20-miler for a fortnight, see how you feel. Don't be dictated to by one-size-fits-all programmes.

If you finish a marathon in a happy state, you haven't tried and you might as well not have bothered. You're going to fuck yourself up anyway, do it right.

For the sake of my sanity, I'm going to focus on your advice! And get running...