Jim, surely you need a copy of the Don Rowland BR wagons, the first half million book? I picked up a copy on a eBay for under a tenner, it has plenty of drawings in it and it a perfect refence on the subject.
Tony
There are no drawings in Rowland, only diagrams. All of which are now readily available on line via the Barrowmore site.
Looking at my numerous photos of BR van ends they vary considerably, Not just in the number of corrugations either side of the vents and bolting but the end - some are semi-circular on the ends, others quite elongated. I suspect the depth may vary as well. One can only presume the ends were pressed by specialist firms and bought in, but I may well be wrong.
Paul