Michell was appointed as surveyor-general at the Cape in 1828, (having probably heard of the post through his cousin Rufane Donkin) at the same time holding the positions of superintendent of public works and civil engineer.
In 1828, Michell was designated as surveyor-general at the Cape, concurrently holding the roles of superintendent of public works and civil engineer. This appointment might have been influenced by his cousin Rufane Donkin.