I think the reason behind this is that the UK NHS is using a lot of budget on long-term ill people who they believe aren't really long-term ill, or who at least could be working. Essentially, they feel they can't trust their employees and want LLMs to do it instead.

So they want LLMs to look at all the files, and essentially kick a lot such people off the NHS. That's what they're paying for.

In other words they want to "Elon Musk the NHS, DOGE-style".

This is, of course, highly illegal to do. There is no way giving medical data to a US consultancy does not violate UK and EU law something awful. The government knows this, does it anyway. Which is one reason you won't be able to do anything about this: the government has zero intention to respect the law in this case. You will, of course, be expected to pay your taxes correctly.