BA also has the option to switch suppliers or even switch the champagne altogether. I.e. continuing with LPGS at a potentially higher price for a few weeks until an alternative solution has been found. Perhaps switch to Bollinger La Grande Année even if it’s just for bargaining power. In addition, I find it pretty bad that BA doesn’t seem to keep any stock of LPGS - if you book BA F as an Emerald and then get Henriot in the lounge you can’t help but think “why did I bother paying for F”. So I am not on the same page with your explanation of BA’s on-off relationship with LPGS.