Shame we didn't meet his son in 2016
Just watched this on iPlayer and was actually pleasantly surprised. I was never a huge fan of the show back in the 90's but did watch it on occasion and always liked the time travel premise.
Assuming it isn't coming back so....
It's a shame they couldn't tie up a few loose ends such as Gary bumping into his son (who would be around 70 in 2016) and discovering that he was a famous scientist who had been working on a time travel experiment in the early 90's (when he would have been in his 40's) and his lab just happened to be near Duckett's Passage. Something went wrong and the research was abandoned... leaving Gary to discover the portal.
So his experiment turns out to be the very reason why he exists at all (the loop was predestined).
Just an idea.