I've supervised Masters theses and PhDs in the US at a top institution. No one can do a part-time PhD; it's just so much work. The fact that Reading is willing to sign a PhD with basically no research with one publication in an absurd venue is pretty sad. This wouldn't pass for a thesis proposal here!
It's also very sad that this person's adviser is willing to shirk her responsibility and just let him go without a proper education. Part of the problem with the UK is how funding works encourages this reckless and pretty selfish behavior on the part of faculty members for their own benefit.
A PhD is supposed to teach you how to do research, pick a big problem, break it down in several different ways, push the state of the art several times, and learn how to communicate in reasonable venues. Looking at his thesis and publication he's done none of the above.
As for the UK vs the US, I have collaborators there and have postdocs from there. A US PhD is like a UK PhD plus a postdoc. You're basically just halfway toward being able to do good research by the time you're done a UK PhD so standards are pretty low, although not this absurdly low. There's a reason why getting a faculty position in Europe with a European PhD almost requires a US or Canadian postdoc.
As the parent said part of what the PhD gives you is the access to people that are smart and capable. Being around them will make you much smarter and more capable in ways that are intangible but obvious in retrospect. Doing this remotely defeats the whole purpose. Because of this in the US you would never get into any reasonable (top 100 or even lower) grad school if you said you wanted to a part-time PhD.
That being said. A real PhD is worth it. You'll learn a lot. You'll work very hard for 5-6 years and at the end you'll be far better equipped in any environment.