I noted someone asking for champagne in WT+ the other day and saw they were given some sort of (cheap looking) sparkling. I didn't know such a thing existed apart from pre-departure fizz in WT+. What is it and does it taste..ok?

As an aside it was nice to get the new CW glassware and indeed CW fizz in WT+ the other day - much better than the off sweet sparkling usually served pre-departure.