I've never been to London, so I can't speak on the accuracy of it, but even if it isn't, who cares?
I came to this game after loving watch dogs 1 when it came out... then later trying watch dogs 2 and being severely disappointed (though to be fair, i tried it late, when other more advanced games had been out), and expected to be disappointed by this game... and I was severely wrong.
I love this game!
First thing I noticed was the graphics are beautiful! I also LOVE that it takes place in London. Idk why because I like America just fine... just is a fresh change from other games I played. It's always New York (sooo often), or Miami, or Los Angeles, or whatever...
I thought the lack of character creation wasn't good, at first, but I'm glad it wasn't there, now. How they did it, being able to recruit and play almost ANYONE you run into on the streets, was such a unique and awesome way to build your team and explore. I actually care about the NPCs on this game, as they all have their own personalities and skills (sometimes flaws) that make them so interesting.
There are so many various voices and accents, and even varying levels of accents in it... it's just amazing. and to think of how much work had to be put into it, as any one of the characters voices and personalities could be in any cutscene or part of the story... they all had to have voice acted out every line in the game. it's astounding imo.
The missions are very fun and various, and they mix it up enough to where it doesn't feel like you're just doing the same thing over and over and over.. as well as allowing you to approach the missions in whatever way you like (for the most part. some require more stealthy tactics and some seem to require more aggressive tactics).
The ONLY real criticism I have is the lack of stuff to do in online mode. there are missions here and there, but in free mode, there's no point in grouping up to work together to accomplish them, as only 1 person gets credit (unless I'm messing it up somehow, I don't see a way to group up in free mode). I won't say anything about the multiplayer missions, as I haven't tried them yet.
Either way, even just the story mode make this game gold. I'm looking forward to my 2nd play through, as i don't imagine I'll get the same characters (they seem randomly generated... well within whatever parameters to keep them as viable characters).
Anyway, there are my thought on it, as succinct as I can be.