Jones hit my personal interests in two respects in particular. He was the script editor for Here Come The Double Deckers in 1969-70, and is credited with writing or co-writing 9 of the 17 episodes of the show - in fact he probably really wrote them all, that being the role of a script editor in those days. I excerpted the pages of the book about Double Deckers here.
But he is also one of the very few people to have both appeared as an actor in Doctor Who, and written a story. (The others were Victor Pemberton in Old Who, Mark Gatiss in New Who, and I would also count Noel Clarke who wrote an episode of Torchwood.) He appeared in the early Tom Baker story The Sontaran Experiment as one of a group of stranded astronauts (who all had South African accents):
But earlier on he wrote the William Hartnell story The Space Museum, a four-part story where the second, third and fourth episodes are about the overthrow of a rather dull despotic regime, but the first is a real work of genius, one of the spookiest Who episodes ever and a good candidate for being one of the best single Hartnell episodes. Here it is:
Glyn Jones reflects on this experience as follows:
There are a few later references to Who in passing, mostly to his novelisation of the story (in which he Tuckerised at least two of his friends). It's a good perspective on how brief his engagement with the show was in a long career. And in general the book is a good read if you skip some of the later chapters.