"May be just coincidence that the poles are nearing end of life anyway and are being upgraded as they role out."
That seems to be generally the case in the 4 or so local authorities in my immediate area. The costs of replacing just the top stem now and still having to replace the pole in 5-10 years is not as economic as installing the LED lamps by default as part of the normal pole replacement/upgrading process as they EOL
Also, for other comments on seeing the sky. Since we got the new lamps down our street, I can actually skywatch from the attic window now, being above the height of the street lamps and very little upwards glow compared to the orange sodium lamps. Still not as good as going out to the sticks, or the dark skies parts of Northumberland, but far, far better than previously.