An interetsig thread and an interesting question.
To me, a "Classic Car" and a "Thoroughbred" are one and the same.
Which of course is precisely why many years ago, the VCC classified them as PVTs - Post Vintage Thoroughbreds.
Now, for example, an Alvis TD21 is a throuroughbred and captures the ethos of its age. To parody Jaguar's adverts of the 50s, "Grace, Pace and Space!"
To me, the MG Magnette ZA/ZB was very much a sort of thoroughbred as it encapsulated the ethos of pre-war MG saloons: which I am sure was the intention. Leather upholstery; veneered dash etc. Same with the Riley Pathfinders of the same era. Provided it wasn't you who had to remove the head!
For me, the later Farini A55/A60 clones, i.e. the MG Magnette, Wolseley amd Riley were simply, as one well known scribe (may have been Bolster??) described them in Autocar as "An Austin or Morris with a false moustache and glasses!"
That said, I ran an A60 clone MG Magnette as my road car for six months, simply as I bought it for twopence from a service customer, since: it was taxed and after we'd dozed it out a bit straight and re-sprayed it it was nice. (It had been parked outside his house and smashed up the bum by a builder's truck!).
OK, I know there ae enthusiasts who regularly meet and extol the virtues of their Mustard Coloured Hillman Avengers; or their dull maroon (weren't they all?), Austin 1800 - or as we called 'em, a Hydrolastic Haggis!
But, but, neither of these awful ugly clunkers can by any stretch of the imagination be called "Classic": unless one means, of course, Classic Mistake!
And, sadly, there were plenty around at the time! From Rootes; Ford, BLMH and Vauxhall!