Glazed extension - Please tell me your experience

[MH0084]

Hi,
As part of the update of my ground floor victorian maisonette, the architect has suggested we “extend the extension” with a glass veranda/glazing extension.
The area would be an integrated dining/kitchen. I do like the idea as the new but would only use part of the patio that that I barely use as I have a sunken garden. It would help us has a better integration with the garden during the cold months and still enjoy the garden as it is.
Right now, my property is a bit cold in winter but great during summer (north facing) and my only worry now is how this might impact the overall temperature of the house.
Has anyone done anything like this?
(link as an example - mine would be slightly deeper but same style-ish)

www.instagram.com/p/C12KOu0O0JO/?igsh=ZWhkYmhtMjlhb203

Is the side the extension is proposed to be on going to be South facing?

If yes, avoid like the plague. The violent temperatures we get in our south facing conservatory that filters into the rest of the open plan house caused us to start looking at a move within 3 months of moving in.

42 degrees at midday in February, for example. And it has a solid roof.

Winter was impossibly cold.