Ken Livingstone’s architectural unit will be in charge of working out how the Olympic park will be adapted to life after the 2012 Games, it emerged this week.

Peter Bishop, the director of Design for London, said a separate design team from that working on Olympic plans would be chosen by Christmas. He added that Official Journal notices would be issued in the coming months.

Meanwhile, Dan Epstein, the environmental policy manager for English Partnerships, is leaving to join the Olympic Delivery Authority (ODA) as head of sustainable development and regeneration.

Epstein will take over from Paula Hirst, who has been doing the job on an interim basis, in July. Before English Partnerships, he worked as innovation and sustainability manager for the Ashford’s Future delivery board.

Epstein’s appointment comes as the ODA announced it was extending the deadline for contractors to bid for the 2012 Olympic velodrome. The body is to hold a briefing event for potential bidders on 26 June.

An ODA spokesperson said this was in response to industry requests for more information and time. He said: “We’ve had a good response from contractors but a few have asked for clarification on some points. It is a busy procurement period for the industry and the ODA and everyone needs more time.”

The chosen contractor for the Velodrome is expected to be announced in March 2008.