1948 Allard Dolphin.

Keith English discovered this interesting little film of Mr. Dolphin demonstrating the retracting coupe roof.

Allard did make some ugly cars but this doesn't look too bad. They also made so many variations. Like these woodies for example.

I must say that the Allard J2 would be second on my wish list behind the Vauxhall 30/98.
Anyway regarding the retracting roof, Peugeot had them in the 1930s.

However, the Allard's is the first articulated one. Both of them preceded the Ford Sunliner by a fair margin though.