I think PYE does not have an online store; years ago, they were designing one, but that never got off the ground.

I have not seen the CX-style pyjamas being sold in the PYE stores for a few years now. Do note that the version given in First Class and the version sold in store are different. The CX version is made with organic cotton (and is of a larger/looser cut) vs. the sold-in-store version made from "premium cotton" (whatever that means). I bought L size in store, but only needed the M size in First Class (and even that was slightly too big).

I have not travelled for almost two years, but luckily still have about 20 new CX First Class pyjamas left, in various colours. And, also rotating through another five of different colours to sometimes wear as my work-at-home loungewear during COVID.