Bruno said:
Just less than 100 years later (1935) an elderly friend of mine bought her
new house for £425, which is now worth about £175k
I'm gonna take a completely wild guess and say about £1.5M
I'm curious as to why you bother to relate the anecdote of your friend's
house, if your guess really is "completely wild", and hence not based
on the anecdote.
Your guess is evidently not based on it, unless you presuppose whopping
negative inflation in the previous 100 years. From 425 to 175k is a
factor of over 400 for less than half the period we're covering.
Naive extrapolation would support a factor of 1.3M leading to a
value guess of £27,000M. That's clearly rubbish, and if we were to
suppose that today's properties are overpriced by a factor of 10, the
70-year factor becomes 40, and the 165-year factor 6000, supporting
a more reasonable guess of £120M.
That's probably still rubbish, as it's too naive and makes no allowance
for inflation having been both positive and negative. And house values
are not a good measure. It would be more sensible to look at incomes.
Today, a butcher, baker, or electrician would be doing well to earn
£20k a year (net).
How much would a butcher, baker, or candlestick-maker have earned a year
in 1840? Perhaps £200? If so, the fortune is equivalent to 100 yearly
incomes of a trader, or about £2M, which is very close to your guess.
Careful reading of Bronte must surely give some hints about typical
incomes.