Mississauga is close to Toronto, so I checked the Toronto newspapers, but didn't have any luck. In the Canada Gazette of 1981, Vol. 115, p. 114, a Royston Clifford Osborne is listed in Mississauga and above his name is a Barbara Florence Osborne. Unfortunately, it's a snippet view on Google eBooks, so that's all I can see and the federal government only has copies online that were published after 1998. Very frustrating!
I'll private message you with some further information I just found.