I do like a nice 3-speed roadster, even the lesser known ones.
I can clearly remember seeing Vindecs around in the late 70's and 80's in reasonable numbers. Almost all were 3-speed roadsters, plus a few Shoppers. Don't recall seeing any racers personally. They were nowhere near as common as Raleighs (but then what were?) but they weren't super-rare either. Much like Elswick-Hoppers,
Halfords brand (not Apollo) and Universals, and Puch, they all had a relatively small share of the market but were around in reasonable numbers.
I would be interested to see close up shots of the frame dropouts, to see if they were conventionally brazed or the cheaper swaged flat and welded method used on some cheaper gas pipe frames made by Puch and Kalkoff to name but two. It's easy to just focus on the more expensive quality vintage stuff, but let's not forget lightweight 531 bikes were always in the minority throughout the steel era, and most people rode relatively cheap hi-tensile utilities, of which the Vindec is a typical example.