Rapha, nice but a bit pricey?

The pair of bspoke trousers that came today are definitely going straight back! The jersey and gloves aren't that bad though, think I'll be keeping those.

Back to Rapha... What's the deal with their cap sizing, I ordered a medium and it's really tight. They're sizing puts a large at 60cm+ and my bonce is nowhere near that big. Does anyone know if there is a huge difference between the medium and large?

I have a pretty fat head (always have to wear large sized helmets) and the large Rapha cap is still pretty tight on me. I have several one-size-fits-all elasticated caps and almost all of them are looser than the Rapha one.

Their one-size winter hat is fine on me though.