The threaded bar of the cast iron radiator wall stay can be cut to size in order that you can position the outer plate and nut in the correct position, either on the outer part of the sections or inside the sections as shown on the pictures.
After securing the round base plate and collar into position, simply measure the threaded bar to the required length and cut with a hack saw ensuring that the cut end is then screwed into the baseplate and collar. Finally, just tighten the plates into position.