Serotta School for Cycling Ergonomics

Croc - knee pain could be due to crank length, the position of the cleats on your shoe, too little float on your pedal, your cycling style (do you always ride on a big ring and push, or do you spin?)... lots of things

I'd first go to a specialist bike shop *without" the word "tri" in the name (my local tri shop doesn't even read Cycling Weekly and didn't know about the Shimano 'snapping' hub recall - how scary is that?) and ask their advice first. It could well be free (but it would be polite to buy something !)

I am more of a spiner than a masher...although I am learning to mash more as I am training for 10M TT.

yeah could be position in shoe or crank length....not sure how to evaluate that. The problem is that I can not put my running insoles in my current cycling shoes since they are too snug a fit.
Thing is I am reluctant to buy a new pair unless I know for sure that this is what i need to do.

I don't like much float on my pedal as I feel like I am more likely to overpronate if I have too much room for movement.

Not sure that the shops I know in Scotland will be able to advice me any further given my current bike settings.