Update: received the new clamp and Doughnut from Cain.
Supported silencer box, Undid front U-Bolt. It disintegrated !!
Undid rear U-bolt . came apart no-problem
Pulled exhaust to rear (didn't release rear rubber hanger.) gave sufficient clearance to remove old doughnut, clean up faces.
slip new exhaust clamp loosely over manifold down pipe, fit new U bolt over silencer pipe and loosely secure, ( This was a lesson learnt because first time I fitted the new exhaust clamp only to find it made fitting U-Bolt bloody difficult.)
Insert new doughnut with exhaust assembly paste.
Positioned new exhaust clamp with more exhaust paste and used SWIMBO to put her foot on end of tail pipe and push forward to close two pipes. First tighten forward U Bolt then and secure new exhaust clamp.
With SWMBO foot still on tail pipe, secure rear U-Bolt.
Start engine and allow assembly paste to cure.
No Leaks- job done.
But wait! This is a Morgan. Nothing goes completely well and to plan!!
Found that two of the pinch bolts on rubber bobbins had fractured (for a while it appears,)
4 New Bobbins and bolts ordered to finish the job.
What was the condition of the donut? Was it rusty and did the two sections separate quite easily?