I have sourced the pads (new) which actually appear to fit inside the pleats. I have the correct switches. Need to figure out the wiring, which looks somewhat straightfoward.

On a W123 SA Code 872 was for rear heated seats. I found one example of this in Australia in a 280. It is somewhat rare. The pods are the same, however, from a W116 from what I could glean from the pictures.

Finding those pods is the needle in the haystack.