This is another search that initially threw up many false leads but after letting it sit for awhile, when I revisited it I was able to track down the family quite quickly.
Four medals awarded to N69665 Dennis Maurice Lynch were sent to me in February. Dennis proved to be elusive and there were just three electoral entries and a divorce record. All leads ceased in 1968. It was rather frustrating.
This afternoon I went back to the start and noticed that in the 1949 electoral roll another person named Lynch was listed in the same street but no number was given. Short of any other clue I had a close look at this name. It turned out to be NX191077 Brendon Patrick Lynch and he had the same next of kin as Dennis. This was the link I needed.
Once I had Brendon's address from the electoral roll I did a quick check in the White Pages and I found Brendon still at the same address. I was soon talking to Brendon and will send him Dennis' medals in the near future.
Thank you to Peter W of Mona Vale who found the medals in a relative's possessions and wanted to see them returned.
The returned medal tally is now 1857.