Regardless of the merits of the case, it's interesting to see that a UK watchdog is able to exert such power over a US corporation. There's more background here: https://taxjustice.net/2022/01/18/the-uk-is-breaking-up-face... – they seem to be giving Brexit the credit for UK regulators able to make independent decisions from the EU's own competition regulators
(For a simple example - look at France constantly fining and regulating US tech giants without having to ask Brussels for permission)