I tried a couple of different knobs, I thought about adding a sticker, but in the end I went with eight small dabs of white acrylic paint, which can be cleaned off with no damage to the original paintwork.
It's the only thing I've ever felt was wrong with it, now it's perfect* !
*short of repainting the lettering in the right place
From a tube of artist's acrylic, I can remove them with a gentle fingernail scrape if I ever sell and the purchaser wants it without them, though right now it's far more likely that I'll buy a third one than sell one I already have.