Well, yes. I'm not quite sure why they chose Belgium in that grouping, but if the UK drinks much more Champagne than the US does, that's probably because you can get home grown fizzy stuff in the US (that sometimes calls itself champagne, too), so why import the real stuff? And Germany also has some rather nice froth. If a country wishes to drink fizz, and doesn't grow any appreciable amount, then it'll have to import it. And it's going to import it from nearby countries by preference. Which, for the UK, means France. And by the time you've got to drinking French fizz, you will probably be close to getting Champagne itself.
Belgium, yes, they will have to import, too. But they're a sixth of the British population, so it's to be expected they import less. I wonder how the per-capita figures compare.