Lomas, OMD's operations director, and Stewart-Hunter, the research director, have left the company, as it looks to forge closer ties with its sister network PHD via its Omnicom Media Group media holding company.
Lomas, who had worked on OMD's trading across Europe, and Stewart-Hunter will not be directly replaced. Omnicom Media Group is looking for a consumer insights director and a client communications director to work across both media networks.
The changes are a reflection of research and systems being increasingly handled by the holding group, rather than the individual networks.
The consumer insights director will handle research projects across the group, while the new client-focused role is designed to develop business with existing international clients.