Is it an 'S' type?

Hi Folks. Apologies if this is a bit of a forum hijack but I'm not sure where else to go! I am busy rebuilding a trike which has, I'm led to believe, an 'S' type mk2 back end. My research so far suggests this may be correct, the suspension set up looks right, if you ignore the obvious motorcycle attachments. If anyone can confirm for sure and give me a ball park year that would be great when it comes to getting spares etc, I wonder if the marks on the diff cover might help? I have a couple of questions regarding the handbrake set up. It looks like the original handbrake has been lifted and fixed at 90 degs, there is a short rod to the balance thing then a cable to each caliper. The calipers look identical, they are those big single pot type with the piston that unscrews. One side has a cable that terminates in the multi-spline end that pushes through the hole and springs out to stop it pulling back, the other cable has a completely different end and is held in place with a metal 'wedge', surely they are supposed to be the same, which one is correct? I've attached some images, any help advice much appreciated! Cheers....