Fwiw, the crucial point here is about affordability not value of homes.
The value of homes isn't going to decrease due to the sheer demand.
Where the problem is, is in terms of affordability. And thats concentrated in the bottom and middle of the market and for mortgage holders.
Retired couples living in big houses have been able to keep them after the kids left and they retired because of cheap energy prices. This is about to change and its a fundamental big change to the market which will screw any hopes of the market improving for those buying with a mortgage. This is a huge group who have stayed put for many years who suddenly may change their behaviour. That's a big shift in the market.
Lenders are going to be much stricter with their terms and thats the issue. There will be a squeeze on borrowing as lenders are more exposed to defaulters.
The top of the market is where I think its dead interesting. Houses aren't going to lose value due their square footage - if small properties are in huge demand they can't, simply because in theory you could split these properties in two or they can be shared by two households.
But they are going to get much harder to sell. Older couples may be desperate to sell free up their equity and to avoid huge bills they don't have cash for. So I do think there will be good deals to be had for some moving up the ladder. Others older couples may seek to downsize themselves with what cash they have, but will rent out, perhaps at a more favourable rate because they struggle to sell. Large properties are likely to take longer to sell as there just won't be the number of people to buy. But crucially they won't lose a huge amount of value either. Around here large 4 bed detached properties are now going for around £700k. But a 2 bed half the size is going for at least half that, and there's the rub.
I think we will see more large proporties repurposed into two or more smaller ones in certain areas by developers for this reason. But that won't happen everywhere and is subject to planning permission that many councils will be perhaps reluctant to approve due to things like parking and provision of local services such as schools and healthcare facilities.
In practical terms places which are NIMBYheaven will now face a dilemma between giving planning to divide houses and giving planning for new builds. I also think its going to shift the market in terms of what developers build and what buyers (and voters) want. The trend has been towards the large detached executive house because that's what makes the most profit. I don't think that's going to hold true going forward. It will be much more towards cramming in townhouse semis or terraces on the same footprint. Which again I know NIMBYville areas don't like. That is until many realise they want to downsize but can't...
What the potential downsizers want and need is the real thing to watch here. That's what's going to drive market forces.
Not overall market prices, because its all about affordability not value now.