Thanks again friends.
The only viable technical option that I see is re-shelling from a donor with perfect bodywork.
As MJ is suggesting, it should be 3.7 donor with 75% of them already being rear ended in the past, with only 25% in good condition, which significantly complicates things.
This can now take years and years of waiting patiently.
Fortunately, I have place in the garage to keep it pretty much forever until a good opportunity emerges.
I'll see what insurance will offer me, but if compensation is capped at market value I don't even see a point of talking to these people. In terms of trying to demonstrate it was actually a 'cherished car' I see no baseline for comparison. A couple of examples were sold at
www.4starclassics.com, but they don't publish prices for what those cars went.