The doors don't shut fully so I tried jacking up under the main crossmember which showed how much the structure has collapsed.
In fact looking underneath there is virtually nothing left.
I reckon there is little chance to rebuilding unless I can fabricate a jig to hold front and rear section in the right positions.
I'm not yet classing it as "beyond repair" but it isn't far off.

Has anyone else tackled a convertible with similar serious rot ?
Paul Humphries