15bob = 15 shillings = 0.75 pounds. Assuming no vacation that’s 52*0.75 = £39 in a year. So what is 39 quid when Dickens wrote the book worth today?
Hint: it’s not over $27k, no matter what the meme that got him going says.
Let’s figure that Dickens wasn’t totally up to date on the going cost in 1943. Let’s say that he was almost a decade behind, and go with 1935…oh, wait, that’s the exact same as ’43….
Go ahead and check his math.