MGBA,
Everything that is happening through PAYD is being mandated. As for the setting of prices.... the only reason the core menu stays low is that it has to fall in line with Standard Food Charges for other stations.... A La Carte menu prices are not hugely expensive in the grand scheme of things, but they are usually double the price of the core menu.
As sadly we don't have CORE menu Theakstons Best.... I can only presume that they will charge whatever they think they can get away with!
BK