About the execution, the piece begins slow and repetitive. You start with 'I don't know how he found my address' and then tackle this same problem a few paragraphs later; it even answers it, making that first line feel both unnecessary and outright conflictive to the rest of the article. We keep going and the rest of the article feels rather rushed, especially from the point the two enter Mrs. Elizabeth til Wolff leaves after London and the cat. Also, the explanation that the cat and London gave felt very info-dumpy; not natural at all. They just happened. To finish this, I think the interview should be in a division of some kind, to separate it from the narration part of the journal (But that's more of a 'I'd prefer it that way' rather than an actual issue so it's fine as is XD)

About grammar, my first problem is that dialogue isn't ended with periods, instead leaving them open and adding a comma after. I think you need to add punctuation inside the dialogue. (There are more grammar mistakes but I don't have time rn. If you ever see this message, please PM me here on wikidot and I'll send you a list of grammar stuff to fix.)

Overall, I wil downvote this, because there's a lot of faults, but I think the main idea here is solid, and it's interesting to see Mr. London's past, since he is a rather mysterious fellow. I would recommend rewriting this piece after the contest~

As to why London didn't show his surprise when he saw the dark-as-night cat, is that London is a very shy and closed person, who doesn't really like showing emotions. He usually hides behind the mask of his self-centredness and charisma. I don't want to spoil much of his personality, since I want to keep him a secretive character.

Thanks for the reply!

That said, the surprise twist here felt a little forced, it was like William and London were two complete strangers until… well, until they weren't, did they both show no hints of emotion after finding their long "lost" friend?

I don't think I can be of much help with grammar since English isn't my first language and stuff, but I found this paragraph? looks like something's missing at the end, don't think you meant to do that.