This is often sold around 15-16pounds, including right, now at waitrose. This works out just marginally cheaper and ok you get a free bottle of Cava (which will taste awful next to the CL but could be used in cocktails I guess).
Decent deal :O New year's Eve is coming ;) cheer's
Quidco 7% too! The Crémant de Limoux is great value. So you could get a case of 12 plus the free champagne the OP mentioned for £107.88 🥂