I'm not sure that works. There were 20 shillings to the pound.

So £0.75 a week.

This inflation calculator:

https://www.bankofengland.co.uk/monetary-policy/inflation/inflation-calculator

£75 in 1843 is equivalent to £8,310.96

So 15s then is equivalent to £83.11 a week, £4321.72 a year.

40 hour week (which is implied to be too low). ~£2.08 an hour

So if he worked over 40 hours you're talking a sub £2/hour wage. Around $2.70 in US money.

I suspect the stat relies on converting to dollars before applying inflation as GBP to USD was about 1 to 5 then instead of about 1 to 1.33

It's fun but I wouldn't want to denigrate Dickens by saying he got poverty wrong to make a political point.