Triumph published guides to how long their service garages should expect to spend on a job. The time taken to do a service or repair job obviously depends on what tools and experience you have. With the passage of time cars tend to get harder to work on. Here are some downloadable PDF copies of these Schedule of Repair Operations Times.
A combined edition that covers GT6, TR4A, Herald 1200/1250, 1300, 2000 and Vitesse 1600/2000
A guide to the times to repair Borg Warner 35 automatic gearbox