I am not yet used to the concept of electronic devices posting to forums for the sole purpose of wasting my time
It's not your time they want, George, it's your money. Some Chinese sharks on Aliexpress have refined their AI-driven "chat" so as to baffle customers into giving up their claim to a refund. I'll report back when I've kicked them in the goalies at least a million times what I've lost.
Returning to the actual subject of the thread:
If I were a bicycle manufacturer who went to the design cost of making a bike weighing only as much as necessary to make it fit for purpose plus a conservative or even generous margin for safety, I'd be very brassed off if random bicyclists without engineering training -- which lets you out -- started sticking on stands on clamps that could crush or fracture carefully calculated and chosen thin wall tubing.
On the other hand, I think it is pretty stupid to build a touring bike on which a stand isn't standard equipment or an option, but in any event allowed for in the design, among other reasons as a control on random owners' foolishness. It is another example of the all-too common error by bicycle designers -- even good ones -- of not putting their minds in gear, of simply not thinking about which road bike conventions don't belong in touring bikes.
All the same, I would reject the common clamp-type of stand-fixing as simply too likely to cause a problem. It should be clear that I consider this near-universal rejection of bicycle stands among bicycle-makers as a prejudice of old racers, but in the specific case of stands which require clamps to thin-wall steel tubes, I absolutely agree with them that they are too risky in DIY hands.
Instead, I like the tab-type of stand-fixing that ESGE, and presumably others, offer. This consists of a thick, tapped, rectangle of metal soldered or welded under the non-driveside chainstay as near to the axle hanger (or possibly the disc brake brace between the chainstay and the seatstay) as possible, and thus shares the torsional load between two frame tubes. Or even three tubes as on the photo of a mixte touring bike with a 180kg load capacity.
Note that the photographed bike has a disc reinforcement (the perforated half-moon) on only one side of the frame whereas in your photo of your yellow Thorn both sides of the rear triangle are braced, so that, all other elements being equal, the Thorn 4-tube rear end could easily be as strong as the mixte 6-tube design once the axle is bolted in.
ESGE tab-mount stand, mounting detail left, load paths right. If you want to study the arrangement on a sharper picture than this screen dump, there's a PDF at
http://coolmainpress.com/AndreJute'sUtopiaKranich.pdf -- just keep scrolling down in it until you see the photos above.
