Here's what the chromed unit looks like with a Sierra master cylinder fitted:
Dual Diaphragm Servo with Master Cylinder by
Mash_Tun, on Flickr
The adapter plate needs a little cleaning up and then painting so this was just a trial fit to see that everything lined up and went together correctly - and it all does just perfectly, I'm very pleased:
Dual Diaphragm Servo with Master Cylinder by
Mash_Tun, on Flickr