Grand Designs Australia was filmed in 2009 by the Lifestyle Channel, who chose Maddison as someone "who could best articulate the grandeur of Grand Designs and also the Australianness we are looking for." The series was first broadcast to Australia in October 2010. It was subsequently broadcast by Channel 4 to the UK.
Maddison was named 'Best New Talent' at the 9th annual ASTRA Awards in 2011.
Maddison is a practicing architect, having started work as a student in 1978 with Peter Crone & Associates. He subsequently worked with Morris & Pirotta Architects, Cocks & Carmichael Architects, and was a Partner with McIntyre Partnership Architects & Urban Planners, before founding his own practice Maddison Architects Pty Ltd in 1988. Peter is a long-standing member of the Australian Institute of Architects' Small Practice Forum and Awards Taskforce.