Last month, the former managing director, Marc Mendoza, was made the chief executive of the Havas-owned agency after Bob Offen vacated the position in order to concentrate on his other role as the head of global operations.
Mendoza now leads a team of five managing partners including Stead, Oldham, Simon Sadie and the former finance director, Mike McElhatton.
Mendoza said: "This new structure very much plays to our strengths and it will help us to continue the successful development of our product offering to clients. I believe they have complementary skills. Dominic will have responsibility for the business and commercial side of MPG working with me, and Marie will focus on the strategic output of the agency working closely with Simon Sadie."
MPG's international media director, Tim Scott Hunter, is leaving the agency to join the television production company Coast as a managing partner.
The international department will be run by Mark Finney, currently the international board account director on Intel, and Andrew Norris. Norris was the international account director on Orange and Airbus, and has now been promoted to the board.