Lest we forget that Donald Healey and Carroll Shelby had a long history together.
Shelby even approched Austin with the idea to buy Healey chassis and put Ford V8s into them to create the first Shelby "Cobras", but Lord Nuffield wouldn't go for it. Shelby then went to AC and bought their chassis instead.
Too true that the value is only what someone will pay for it, not what it cost to build it. Still true for a custom, or hot rod, or restomod just as it is for an original. There just aren't anymore just like it to set a standard value like with a true restoration.
C Ya,
Mark