This is disgusting.
If you’re in the UK, stand up to the legal bullies. Ask your MP to change the libel laws to reverse the burden of proof, and only allow actual UK citizens (and not companies or associations – foreign or not) the ability to sue.
I was once sued for defamation and had to settle as I had zero resources to fight it, and so had to apologize. I know how hard it is to state something you believe (or know) to be true and win in such cases.
Reputation is hard won, and I know how damaging hurtful or factually incorrect statements are, but the UK libel laws are legal censorship instruments, abused by anyone with enough money to sue.
In this particular case, it looks like observable facts, peer reviewed studies and a valid opinion based upon those observable facts and studies will lose. It’s a sad day for the UK when facts are not a valid defense.