Hmm, interesting. No specific details on how they’d deal with companies not doing business in UK. Oh well.
Discussion
They can sue you I guess, and UK has a lot of sway internationally
"The Act applies to services even if the companies providing them are outside the UK should they have links to the UK. This includes if the service has a significant number of UK users, if the UK is a target market, or it is capable of being accessed by UK users and there is a material risk of significant harm to such users."
This means that anyone who runs such a service can be denied entry to the UK, can be charged in abstentia and prosecuted on entry to the UK, or in extreme cases (and if treaties exist) can be extradited to the UK.