The History of the Retriangulation of Great Britain
The History of the Retriangulation of Great Britain 1935-1962 is the definitive official account of the 1936 retriangulation.
It was published in 1967 and comes in two volumes. Volume 1 is a book of around 437 pages, including a number of photographic plates. Volume 2 consists of a box containing a number of maps of varying sizes.
Original copies of the book, especially volume 2, are difficult to track down, and would certainly auction for several hundred pounds.
A searchable PDF scan of Volume 1 can be downloaded from here (17MB)
The scanned diagrams from Volume 2 can be downloaded here (354MB)