These are all solutions that ignore the main problem. They literally cannot build enough properties (whatever they are) to fill current demand. Even if they relax the regulations that we currently have in place. Even there were enough properties built the infrastructure for utilities can't be scaled easily. There are issues building new properties right now because the electric grid cannot handle the combination of that and large data centres.

Since supply of house cannot be increased to solve this problem, you need to lessen the demand. The most obvious way to do this that I can see is to put a cap on immigration that is much lower than the number of people leaving (about 400,000 people leave the UK each year). However for various reasons this is seen as absolute verboten.

BTW, I know exactly the type of buildings you are talking about (we have them in Manchester) and they are typically look awful and usually start falling apart after shortly after construction. They are also not very nice to live in (I have lived in one for short amount of time).