Topping up on this...
EasyJet (offshore, back-office team, and my only contact) refuses to acknowledge this product exists.
I initiated a chargeback through Amex, and EasyJet countered with a bunch of nonsense (proof that I took the flight?!), but crucially they provided a printed copy of their terms and conditions - which are more detailed than the 'easy read' format which they usually direct you to. The irony of them providing the evidence that was required (as their defence of the charge) is not lost. Anyway, after some further searching, I found an online version of the ts and cs - currently
here. The relevant section is screenshotted below:

Pretty clear to me - and yet the back office team still, refuse to acknowledge that this section even exists. Anyway, I have gone back through Amex for the dispute with this evidence, but it really shouldn't be necessary.