I’ve taken a couple of short band CE flights the last couple of days and on both of them Monopole has made an appearance. On MAN-LHR there was a mixture of Champagne de Castelnau and Monopole. On my connection there was only Monopole available. Drinking the two side-by-side, I definitely prefer the Castelnau.
I suspect this is a supply issue rather than a change in the offering.