As the diagram book lacked any sensible order to it, index sheets produced to assist in finding the relavant information. This was long before class numbers were thought of, so the vehicles were identified first by gangway (both ends, one end or none), then split into vehicle types. The sheet for each type (such as driving motor open second) would then be listed by lot number and reference the page / diagram number for each. The sheets from the index book for DMUs are reproduced below, the full set of coaching stock index sheets (hauled stock, DMU, DEMU and EMUs) can be found on the BMRG website.
|Section 7||Gangwayed||Cover||Index of Sheets||Sheet 200|
|Diesel Mechanical Stock||Sheet 201|
|Section 8||Gangwayed One End||Cover||Index of Sheets||Sheet 230||Ammendment|
|Diesel Mechanical Stock||Sheet 232||Ammendment|
|Section 9||Non-Gangwayed||Cover||Index of Sheets||Sheet 260|
|Diesel Mechanical Stock||Sheet 261|
|Section 10||Gangwayed||Cover||Index of Sheets||Sheet 300|
|Diesel Electric Stock||Sheet 303|
|Section 11||Gangwayed One End||Cover||Index of Sheets||Sheet 320|
|Diesel Electric Stock||Sheet 321|
Also part of the diagram book / index was tables showing the 'distributed' weights that could be carried in the brake vans. These sheets are courtesy of David Faulkner - Sheet 1 - Sheet 2 - Sheet 3. I've also found this partial diagram index made by a member of staff.