As far as I can tell Knox is still with...

As far as I can tell Knox is still with Hatch!
http://www.hatch.ca/About_Us/BoardofDirectors.htm
Why would he quit Hatch to join Downer?
Maybe this has something to do with it...

In Australia, Hatch has 9 offices, all of which will be managed from the Australasian headquarters. Hatch Asian operations will also be supported from Brisbane. Hatch’s Australian presence increased in late 1999 through a
merger with BHP Engineering, and again through a merger with
Kaiser Engineering – resulting in about 1400 people in Australia. Hatch was established in 1955 and its growth over the years reflects our ongoing focus on assisting our clients in their efforts to be successful,” Geoff Knox, Hatch Managing Director for Australasia, said. “We want to be the best at what we do, not the biggest. So our growth over the years is a function of extending our services to best meet the expectations of our clients.