The Bohemian Doctor
First seen during the Think Tank Scandal, this man initially appeared to be a replacement for the UNIT Doctor as scientific advisor to UNIT and has, indeed, been talked of as UNIT's scientific advisor by those involved with him. In contrast to his predecessor, this Doctor exhibited the tendency to arrive just before an incident and disappear immediately afterwards, like the rest of the agents bearing the name the Doctor and only stayed in the role of scientific advisor to UNIT for a short period of time.
The Doctor was involved in a variety of incidents in the late 1970s, only a few of which directly involved UNIT. His activities with UNIT included the Loch Ness Investigation as well as the Devesham Incident and the Chase Mansion Affair. His final appearance to date, which was independent of UNIT, was during the St Cedd's Incident at Cambridge. Despite being officially attached to UNIT as scientific advisor, this Doctor rarely made use of the connection, and then only when actually working with them. He seemed to be very reluctant to accept authority figures and generally refused to fit in with any of society's norms.
The Bohemian Doctor was tall with dark curly hair, and a broad toothy grin. He always wore a very long trailing scarf and, usually, a broad-brimmed floppy hat with a baggy jacket, looking very much the bohemian eccentric. His behaviour fitted his image very well, as he tending to sprawl in unlikely positions and preferred the contemplative approach to situations, although he has been known to use excessive amounts of force on occasion. He carried, and frequently used, a yo-yo as well as carrying around a bag of jelly babies, which he often offered people, presumably as an attempt to put them off guard. He was irascible and moody, and sometimes totally oblivious to his surroundings. His character generally veered from a total aloofness to an impatience with the world.
He, like the others bearing the same name, is an enigma. His activities around the UK suggest that he worked for some kind of covert organisation, yet he totally ignored his UNIT connections. We can find no evidence of a connection to C-19, or any other secret organisation, other than through UNIT. Though his similarity to the other Doctor agents suggests that there is such a connection. His activities are also connected with the unusual incidents that UNIT specialises in dealing with. In short, his affiliation is an enigma that may not be solved for quite some time.