I will go out over the weekend and try to ascertain what my worms are using your chart.
Not my chart, Pete; Imperial College Research Centre's: in a world where a blackbird is a black bird but a black bird is not a blackbird, I'll rest content that Rayner and I know what a redworm is and what brandlings are. Everyone else can catch up in their own time.
In the North-west, at least, everyone distinguished redworms from brandlings as per Rayner's points, and we never saw the likes of the modern dendra. I wouldn't like to say when they began to be bred for the fishing market, but iirc some farmers diversified into it during mid-90's BSE, and Dutch ones were using these new super-worms to break down composted stuff. I also recall, but this is not the kind of stuff that gets uploaded so I can't find any online, old angling bait guides often advised redworms over brandlings due to the latter's bitter fluid. But didn't say how they knew what they tasted like.