Currently living in zone 2 north-east London and house prices have seemed pretty flat for the last couple of years. Flats have had a surge due to current stamp duty holiday... and prices outside London seem to have increased a lot with people anticipating a permanent move to remote/hybrid working.
Taxes on empty properties aren't high, but you still need to consider maintenance... and there's an opportunity cost of leaving a house empty rather than renting it out.
Just interested in your data - thanks!
Update: found https://www.actiononemptyhomes.org/pretty-vacant in one of your sibling posts - was that what you were referring to? I just read it (on my phone, so might have missed it), but didn't see any numbers for investment returns here... and there was a fairly-extensive section talking about London property being used for money-laundering instead - is that what you're referring to?
About once every 2 weeks his son pops by to make sure the house has not burned down or had a pipe burst.