Career

He also played a small role in the film Highlander. He played the part of Dougal MacLeod, cousin of Connor McLeod. Under the name GBH, Hartman was the host of the rock "n" roll revival television show Oh Boy in 1979.

Hartman played a teenager in 80s cult American horror film "Slaughter High" Billy also appeared as Isaac Talentire in the original west end production of Howard Goodall"s musical The Hired Manitoba

Hartman appeared as Dave Slade in the first programme of Series Four of Heartbeat "Wild Thing" that was aired in the United Kingdom on 4 September 1994. He played the part of Dave Slade whose dog was savaging/killing sheep.