I have the fourth edition, which I think did correct a lot of the mistakes in the previous ones.
I think I know what a HND is (I grew up in the UK), and I guess PEfI makes sense there.
It’s always a problem when you pick up a book aimed at an audience with a different background to your own. It’s not much use sitting there thinking “Why didn’t they write a book for me?”. I just landed on it because it has a reputation for being an easier introduction to electronics than TAoE. I think that it is a good book for a very quick overview of things, but I definitely feel like I’m going to need to go back and cover a lot of things “properly”.
There’s a thing I’ve started noticing with electronics that was brought into relief in the last few weeks while I was studying some power supply stuff. It’s not all that hard to pick up enough knowledge to use things, without having the first clue how you would build one of those things yourself. It’s easy to wire an op amp up to do something, but the step from that to being able to design an op amp yourself feels huge. Some of that need to do things “properly”, for me at least, is about trying to fill in some of that gap, because for some things it feels as though you do need some of that gap filled to really understand what’s going on when you use these things.
As for the other things you mentioned: FPGAs = fun, railway signalling standards = insomnia cure!