I am bit odd, that's for sure! 
I didn't hear the robbery storylines - it was in the 60s, I think, not long after the Great Train Robbery. Being an ubernerd, though, I have read a few books about TA and it seems that after a decade of huge listening figures in the 50s when very few people had TVs, in the 60s there was an inevitable decline and the production team thought the solution was to have lots of sensational stories, including a train robbery. Adam was kidnapped as a baby too - nobody ever refers to this now because I think subsequent Editors have decided that's all best forgotten.
You missed a treat not hearing Nelson Gabriel. He was the son of Walter Gabriel, who was the resident yokel/lazy farmer for the first few years, the contrast to the good, conscientious farmer, who was Dan Archer, David's grandfather, back then. Nelson inexplicably spoke with a lovely plummy posh accent, totally unlike his father, and eventually settled down and ran a wine bar and an antiques business in Borchester. All through the 80s and into the 90s the wine bar was the setting for many scenes involving the young Shula, Elizabeth, Nigel and Debbie. Nelson was the confidant of all the young people, a wonderful foil to the staid middle-aged Archers and Aldridges. Happy days.
Here's a Youtube clip I've just found: