We decided that 30mph was a sensible limit in built-up areas and thus for many decades, every single driver in the UK has been taught this limit before being granted a license. There is little need to signpost 30mph areas because this is the default limit in built-up areas. The limit that all drivers are taught to abide.
For a local council to buck this, and thus have to put £1.3M worth of signs in our local area (to be ignored by nearly all) is hugely questionable. It risks making a mockery of all speed limits, not just those at 20mph.
Prosecuting any driver for travelling at 25mph is farcical, which is why I support the police’s Community Road Watch efforts, which do not impose fines on people for travelling at 25mph, but instead put a visible police presence on key streets, making all drivers think carefully about how they’re driving. Speed is just one element of safe road use.
You might find it relaxing, but I’m not sure the ambulance driver trapped in needless gridlocked traffic behind you would feel the same.