The one you made David looks to be about 45mm shorter than the original, the original was approx. 200mm in height when stood on end, the radio is approx 250mm wide, take away the thickness of both sides of the cabinet and the plywood blocks and that leaves a nice snug space for a PP8 battery replica and its connector terminals without it sliding around inside the radio.
Now found a link for the full book referring to the book page link I posted earlier that gives battery dimensions for many types (latter part of the book for PP8 etc) if its of any use:
https://archive.org/details/CROMPTON...renceBook3rdEd.
Lawrence.