The man in Room 17 was Edwin G. Oldenshaw; his colleague was Ian Dimmock (in the first run) or Imlac Defraits (in the second). This therefore meant that, combined, they formed the EGO and ID.
For the second season the opening titles were revamped. One of the briefly-glimpsed documents is a memo from the Director of Public Prosecutions to EG Oldenshaw and I Dimmock. For this season alone, however, Ian Dimmock was replaced by Imlac Defraits, suggesting the title sequence was compiled before it was known that Michael Aldridge would not rejoin the show for this run, having fallen ill. (He returned for follow-up series The Fellows (1967).)
Promotional material at the time clarified the series' set-up: "The two stars, Oldenshaw and Dimmock, work in Room 17, secret headquarters of the Government's Department of Special Research, hidden away in a windowless Victorian turret on a Georgian house somewhere in London. Their job is to solve cases which either defeat the Government's conventional security services or need special powers of action. They are answerable only to the Prime Minister."
The amusement using black and and white stones, much enjoyed in Room 17, is Go. Considered the oldest board game still in continuous play, the abstract strategy game originated in China over 4,500 years ago.
The two seasons were sold to Australian television as one 26-part run, whilst the second was still airing in Britain.