In my opinion, this is a poor installation.
I would be embarrassed if I had installed that for a customer.
things I don't like,
Extra hole in door filled with silicone
cable is not well supported over the full length of installation (bell wire)
no cable gland on transformer box, therefore cables are unsupported and easy to get pulled out.
I would have preferred to see it wired to a fused spur instead of being on a plug and socket.
the guy installing it appears to have a limited understanding of what he is doing.
Edit,
Also, WOW, if he thinks that particular installation is so good it is worthy of posting a video online showing off his skills.
I would shudder to think about the ones he has installed that are not good enough to show off about.