After concluding an illustrious career in Parliament spanning 27 years, Sir William took up his Surveying tools once again and in 2000 commenced working with Birch Surveyors as a consultant. He had originally established a surveying practice in Pukekohe in 1957, and played a key role in the development and growth of Pukekohe and the surrounding areas in the 1960s and early 1970s, both as a surveyor and a member of the local Pukekohe Borough Council.
Today Sir William spends long hours overseeing numerous land use and subdivision consents, and shares his vast knowledge with the younger surveyors, planners and engineers.
After work, he loves tending to the steers on his 25 hectare farmlet, or sharing his gardening and culinary skills with his children, grandchildren and great grandchildren.