bahco adjustables are a higher quality, they use better steel and better machining than the cheap chinese ones, the modern bahco though heading the game today are still lower quality than the older bahco adjustables which will still fetch £30 for the 8 inch spanner after 20+ years.

the old fashioned adjustables made by a number of manufacturers have the advantage of a spring under the adjustment knob which takes up the slack, modern cheap ones have poor machining and also nothing to take up the slack in the adjuster, thus they can be the most dreadful of things, a good quality old adjustable of the small 4 to 6 inch variety made before the war can be had for around a pound or fifty pence at a car boot sale, look for a good pair of jaws and that it hasnt been overly abused in its use, the spring is in place and that when closed the jaws meet nicely without undue amounts of light visible through them when they are viewed sideways, a most useful tool if you find a good one.
the wartime finish marked tools are produced during the war for various uses and the machining and steel quality can be lower than expected, grease packed unused ones still turn up and may require deburring and a little fettling to use, the steel is also variable in quality, the prewar adjustables are usually a better quality or consistent quality of steel and finish. a little oil on the thread and the sliding parts and you have a good tool for general use where carrying many spanners is uneconomical, such as a toolbox on a motorcycle.

some people have the money and facilities to make up odd items for no reason other than a challenge and a bit of fun, it is uneconomical to reproduce these spanners, though as a small technical and fun project i can see the attraction of it for the person who made the video.

just to add, if anyone wants to go mad and pays the grand sum of ten pounds for a single spanner, i can request them by the box full to be dispatched on receival of funds! they are a common find.