That particular case merely means that the « cheap » stuff is self service but you get something nicer served (a bit like food in GF where an a la menu exists which I think is still the case at LGW). There is really no equivalent in the CCR because nothing really is self service apart from the afternoon tea buffet (which admittedly has champagne and water) so you can’t give better things a la carte since everything already is! If you mean not writing the good things in the menu that would be a different model and one I wouldn’t like for the reasons already mentioned above.

There are off the menu specials (eg Sunday roast or occasional menu substitutions) but waiters announce them as they should. I think the only exception of « hidden » special orders is when people actually want something from GF which waiters can bring easily as it’s the same kitchen but that’s explicitly a downgrade, not an upgrade. Otherwise, I think the ccr model is « restaurant », ie if there is a nice special available you announce it to customers and effectively encourage it!

incidentally, I’d consider myself a wine snob and personally wouldn’t call the ccr wine list mediocre at all. It’s certainly not the best in the world but it includes some good and often one or two very good bottles. Perhaps even more to the point, it’s on par with what ba serve onboard in F which I think is exactly the intention. The few airlines which have truly superior wines in their F lounge tend to serve things of the same calibre onboard too.