As expected one of the solid pipes into the compensator had rusted and broken, unfortunately getting the union off the valve on the car was impossible so ended up removing all 4 solid pipes and the valve. A couple were stuck very tight and took huge effort to remove event when clamped in a vice. Had to remove the 2 most rear sections of the exhaust and 2 heat shields before I could get the pipes off and run the new ones in. I made up 4 new pipes out of some copper I had lying around, used string to measure the lengths and used the old pipes as templates when bending into shape. Cleaned up the compensator and painted in silver hammerite. Fitting up was ok, bled all the brakes with my mightvac and all seems ok, pedal firm, no obvious leaks from the new pipes. While doing it I used the opportunity to torque up the arms correctly, 205nm on the main bolt running between the spring pan and trailing arm was hard work!
Got the first opportunity to try out the car, suspension feels very firm and assured. Need to check the tracking now but I measured the length of the rear track arms before refitting so the same length and it seems to go straight.
I did toy with dropping the rest of the exhaust and redoing the underseal but that will wait for now. Next up is the respray.