Interesting, because I did some research too.
I took a look at some old Voters Lists and the Toronto Star.
In 1953 , what I thought was 'our' house was occupied by John Greenan, mechanical engineer, and his wife Margaret. Their address was RR1 Todmorden. By 1963 their address was 'Woodbine Ave' and they were included in the polling station for Three Valleys Drive. John F Greenan was the President of Don Valley Building Ltd. and Universal Plumbing & Heating Co.
"The first office building to be erected in Don Mills is to get underway immediately. The four-storey building located south of Lawrence Ave E and west of Donway West, will contain 30,000 square feet of rentable space. It is to be called Don Valley building and will be operated by Don Valley Building Ltd."
In 1965, at age 45, Mary Margaret Greenan was killed when she lost control of her sports car on the Don Valley Parkway south of Eglinton. At that time she was living on Brimley Road. John Greenan died in 1970.
I couldn't find the house in the 1965 and 1968 voters lists, although I thought I found the right polling station. But I did find it in 1972, with the address 6 Geraldine Court, and was occupied by Gordon Hall (self-employed) and Lillian Hall.