Places   (Help with places, streets and buildings in Wigan.)

It'll be Parly. Boro., which means Parliamentary Boundry and also Borough boundary. As already pointed out, by Cindy ^^^^, U.D. means Urban District, which is a council area.

The estate you mention is in both Wigan and Aspull.
The Aspull part is connected by Camberwell Crescent, I think, and is a newer build.
Also already stated, I can imagine the area being government land (N.C.B) as the government took over all privately held land which had coalmining activities going on, in 1947.