Propstands were unthought-of luxuries in 1920, so, whether a Sopwith needs one or not, here is the finishing touch to our favourite steeds!
It is strictly a bolt-on accessory, requiring no desecration of the original fabric of the machine, utilising for its attachment two of the (otherwise unused) sidecar-mounting reinforced areas of the frame. It is light, elegant, and fairly unobtrusive, in keeping with the overall characteristics of the machine (in my estimation, at least).
It can readily be deployed and retracted 'from the saddle', and its overcentre spring ensures that it stays deployed, even if weight is taken off it.
Clearly, there are a number of alternative design-detail variations on the theme, influenced perhaps by material-availability, the thirst for originality, or personal taste of appearance.
I do not intend to patent the device: you are free to copy or modify its design as you think fit. That is, if you think fit at all...
Footnote:- The photos are in fact of Version II. Version I (for which this article was originally titled, and which gave a nod to Inventor Extraordinary Bradville Granshaw) was tucked away inboard of the frame tube, but because of lack of space, could not be made sturdy enough to resist lateral loads, and was shelved.
Ideally, the leg should be straight, but I was unable to get the angle of the hinge-tongue right...please consult Euclid and Bessemer for further guidance on this matter, if required.