Front derailleur head scratcher...

By putting an extra one on the left side I was aiming to widen both sides an equal amount, but that isn't possible. Using a hollow tech bottom bracket, so it's only the non-drive side crank that gets attached.

That's true, my shoulders sit an completely different levels after breaking my collar bone. I find I have to counter that into my break setup, otherwise I feel really off after awhile.

Hopefully Look get back to me with a spare hanger so I can make it work without the spacers.

If anyone on here has a hanger that goes on a KG 221, the beers are on me.

Unless your the princess with the pea the you won't feel 2.5mm. You could now just shift your cleat out 2.5mm and bring your foot into the crank.

I have been for a ride and didn't notice it... I was thinking along the same lines as my skating days, when a mm's difference in board width was more like a mile.

i know this is solved but you could have put a spacer between the hanger and the derailleur to push it in towards the frame a couple of mm.

Looks like you have a bolt on front mech mount on your frame. is it tight in? Does it looks straight? I had exactly the same problem on a pre-owned carbon frame with Campag kit. Scratched my head for ages, changing the mech, altering the adjusters, height and angle etc etc. Turns out the front mech bracket had been wrenched and wasn't flush with the seat tube so the mech sat too far out and wouldn't clear the chain when on the smallest rear sprockets.