I thought that the building at the end (the one on which the 'Richmond Buildings' street name is attached) looked like it might be a survivor too - it looks a bit run down. The bricks are probably London Stock Bricks and, like the modernised building, would be the same golden colour under all that pollution.
Yeah, I didn't take a pic of the end building as it's Dean St rather than Richmond Buildings (even if it has the "Richmond Buildings" street sign attached), and is on Google Street View anyway. But I do agree that it probably dates back as far as Nat's time. As for no. 12 it's obviously had a lot of work done to it, but like you say the features are consistent with an old style townhouse rather than some modern attempt at creating a vintage-style building (and the latter would be a complete waste of effort anyway, given the eyesore that's sitting next to it.)
I really enjoyed Steven's perfectly-executed Nat-style diary entry too
And glad that he finally visited the grave.
As for "cabinets"; I concluded that the meaning was as per the Shakespearian-era doc already quoted from. I did find an "erotic novel" from the 1880s called "The Pearl" that referred to umm "her cabinet of love" in basically the same context. I couldn't possibly quote the complete sentence here though
But I mention it as evidence that the usage was still around in the late 19th century, so it's completely plausible that Nat would be familiar with it.
