Bike fit / correct riding position

Low arches, and uber wide fore feet.

You've confused me now though. I went for a ride last night, and made an effort not to track inwards. Didnt require much thinking. It just didnt happen.

Thing is. I had my new road shoes on. Which had loads more arch support than my old NWs. I could really feel it. They're Bonts. I was going to mold them some more to flatten the arch. But it felt quite nice last night (been molded to my feet twice already). Think I'll leave them.

I wonder if that helped reduce the angling in of my legs?

I'm no bike fitter so take what I say with a pinch of salt, but from what I understand, most people require some degree of arch support. Most shoes ship out with insoles that provide close to nil and hence most people would benefit from getting some with some support. How much you need is a little tricky to figure out unless you have one of those fancy esole type insoles which let you swap out different arches. A bike fitter will have a large range of heights to try.

The reason your knee tracks in is due to the lack of a platform for your feet to push against, so your feet will roll inwards. If you conciously force yourself to track your knees straight, you will be loading the outside edge of your foot and most likely end up with sore feet. Wedging will help too if your feet naturally sit at an angle that isn't exactly horizontal. And of course if you have muscle imbalances that doesn't help either.