Owning your own home

I do wonder what’s going to happen with conservation areas and listed buildings over the next 10-20 years

I've wondered this too; living in Scotland in a traditional tenement flat in a conservation area. I've had people knock on the door and offer internal insulation upgrades - but the layout of the flat means there's almost no space in which it could be installed - certainly not without ruining internal timber finishes and plaster cornices, which are very typical.

Roof space insulation makes sense I guess, and underfloor for the ground floor flat, but that means 50% or more of the flats in every 4-storey tenement building don't have any feasible options. Better double glazing would be an idea of course, but if that's done already then I'm not sure how much scope there is for other improvements.

Yup awaiting the same, lots of folks in nice C19th 3-6 bedroom townhouses that have managed OK the last 10+ years with gas bills, but now there is uncertainty and a bit of a wild market these folk are staring down £10k+ gas bills at this years prices and still not exactly toasty warm.

There are ways to try and save as much as possible of the original internal finishs (you can sort of cut cornice off if very careful but theres always breakages).

I would say though in my area at least there is a street where the flats are nice and heatings costs are fine (us) after doing some minor work, windows, close door, block up the cracks, tado and have an upstairs + downstairs neighbour, but then two streets over, its 5 bed 3-4 story townhouses 'worth' £650-850k, £10k+ annual gas bills. Conservation area affects all of us, which requires little to no external changes, slate roofs to be fitted and preferably wooden sliding sash.
Loads of these folks roofs are literally falling in, chimneys are actively collapsing (1 a week ago, 2 in the month before that due to total lack of any maintenance), windows that will never open again as they have rotted or collapsed into position. A lot of these folk way way overpaid for these buildings and then have nothing left to do any actual maintenance on them. Just sorting the windows, doors and obvious air gaps would likely cut their heating bill by a third, yet they either choose to do nothing, or can't afford to make the basic improvements.

There is an older couple inhabiting one of the end of street palaces, in perfect nick, yeah maybe a £mil, however they are 10 years into retirement, and haven't done basically anything to it since they bought it in late 80's, they live on the ground floor as can't afford to operate the rest of the building, yet they won't sell (its their house) on the market as they know it won't get the £mil that they think its worth, but they are amenable to someone young like us, paying a fraction of that in exchange for actually turning it into a viable family house again. A year or so ago we were talking about it with them and they were keen on doing a swap for our flat (£250/285k vs realistically £450k) when they get to that stage, and I thought it was an amazing idea. But with this years heating costs, even if I went around and foam lined the entire building I doubt we would be able to afford it at 2025> energy prices without extreme work (floors out, insulated slabs, hvac system, roof full job, chimneys removed and capped then rebuilt to keep the planners happy, strip every room back to stone and start again).
So, was a nice conversation, but actually would probably take 10 years off my life trying to do up a palace like that.

They’ll have to allow sympathetic modifications to the externals. It’s a matter of time I think.