Literally a large chunk of the ARM core team are in Cambridge including most of the GPU folk and there are a ton of infra and software team in a couple of other UK locations.

On top of that, a big chunk of the follow the sun on call engineering (SRE) are here that look after global infra and most of the European support operation are in Northern Ireland.

Fruit Engineering Ltd. hires brits and contracts with offshore Apple Inc. The former does not have the keys and cannot be forced to do anything iCloud-side.

It's not like corporate doesn't know all the tricks already. The only reason they need is whether the UK market is worth the hassle. That's all.