Council owned ones as well is my understanding. They need to be physically replaced by new ones somewhere apparently, that is one of the stumbling blocks.
I am happy to be corrected on this... although:
Evening Standard article about the council houses
According to Palace's website "capacity in the new stand will increase from around 5,400 to 13,500", so I'd say they're getting stiffed somewhere if it's going to cost up to £100m.
I'm aware that the Leitch stand at Liverpool was substantially altered, but they didn't alter the seat spacing...
Not new exactly, it's another lean-to extension like Liverpool's and the one Palace are proposing.
Grandfather rights mean people can stay crammed together in the existing structure, and only the new bit is actually habitable by normal sized people.