Looking at those Drawings from the 'Super Little Book'. Written by a 'Super Little Author', it would seem to my mind, quite a simple task to fabricate one of those brackets. That would accept this bayonet. Naturally, you would also need the bayonet to hand. To enable correct fitting to be achieved in this instance!

I had quite forgotten about these, as I do own one of these 'Super Little book's myself. Along with a few others from the Same 'Super Little Author'!................ALWAYS a pleasure to pull one of them out & have a read occasionaly!