Did anyone make a correct adaptor for this, or is it a case of getting some good quality stainless steel and making one with a lathe?
Currently running 9mm qr, looking for increased stiffness, but most 20mm forks are a bit overbuilt for my type of riding.

if you have a 9mm adaptor and drill it out to 15mm it works perfectly as the shoulder on the adaptor is the perfect shape and it leaves a good amount of material

I sold mine with the adapation I’m sure if you search back the person I sold them too would send you a pic

that;s the machined/drilled out qr adaptor in the pic

that’s great thanks- did you notice a worthwhile difference in stiffness?

15mm is great, probably not quite as stiff as a 20mm but night and day compared to a qr fork