The Barbican

The apartments are lovely, but the service charges are eye-watering, ranging from around £6,000 per year for a two-bedroom, to £14,400 for the more expensive ones:

https://themodernhouse.com/sales-list/thomas-more-house-ii

https://themodernhouse.com/sales-list/Lauderdale-Tower-II

https://themodernhouse.com/sales-list/willoughby-house

https://themodernhouse.com/sales-list/ben-jonson-house-iii

And all are sold on that weird UK feudal relic, leaseholds, so you're just buying for a certain number of years - a couple of the ones above only have ~80 years remaining.

The inaccesibility for mere mortals ruins any claim it has to being a representative of brutalism, IMO. Of course it looks nice, it was made by the City of London at eyewatering cost with absurd levels of craftmanship. The movement wouldn't have such a bad image if other buildings had that kind of budget for upkeep and gardening. But they don't: they're rotten and barren.

It doesn't actually look nice in person, and the craftsmanship ain't anything to write home about. (However I can believe the claims of eyewatering cost.)

The shoddy windows are particularly easy to spot, even in the pictures in the article. I'm not even sure these would be legal in Germany.