Agreed Dave, the broken upper support shown on the link I posted was of an earlier pattern with support tube welded entirely external to hoop though. Yours I see is of the far superior later design with the support tube welded through the hoop front and back.
I'm guessing my factory 5 link rear relies on a further improvement to a taller hoop formed from heavier gauge tubing , as this accommodates all the suspension loads transmitted by coilovers.
Your 5 link setup has to be superior in many respects Richard, I'd really like to try a Morgan with this arangement.