Harding trained on various excavations with the Bristol University Extra Mural Department and other bodies from 1966; he has been a professional archaeologist since 1971.

He learned flint-knapping from his uncle, Fred, and in only a few months became a skilled knapper, crafting many hunting tools from pieces of flint.

In 1966, while still at school, he attended a training excavation by Bristol University Extra Mural Department in Fyfield and West Overton.

He worked initially for the Southampton City Council Archaeology Unit, combining this with five seasons of excavations (1972–1976) run by the British Museum at the Neolithic flint mines of Grimes Graves, Norfolk.

From the mid-1970s, he worked on excavations in Berkshire, Hampshire, Dorset, Wiltshire and the Isle of Wight for the Department of the Environment (DOE).

[5][6][7] In 2010, the radio series A History of the World in 100 Objects featured Harding speaking on the creation of pre-historic stone tools.