Triumph produced in house training material for their dealers. I have collected some of Dealer Training Notes. Here are some downloadable PDF copies of these notes.

Zenith Stromberg carburetter Dealer Training note- S1040 produced for service technicians in 1976.

Has sections on theory and tuning of carburetters. Covers both bi-metal and wax capsule automatic chokes. Includes diagrams.

Carburetter Dealer Training Note

Tune Up British Leyland Technical Training Series produced for service technicians in 1976.

This workbook specifically deals with the Triumph TR7 tune up in the USA but the information should also be of use for tuning all British Leyland cars of the era.

TuneUp BL Technical Training Service

Weatherproofing Leyland Cars Training Handbook.

Leyland Cars Weatherproofing Training Handbook