Looks quite similar to a Jaguar-engined “special” sold out of the late
Ted Leonard’s collection a couple years back. The front was mostly SS
100, in my judgment. But I couldn’t make out the back. now I understand.
Leonard’s early ’50s “Special” (last seen in France, circa 2010):
Atalanta 1938 LeMans entry (V12 powered, I believe):
BTW, I believe that “special,” provenance unknown, was likely built by
the Gantry Bros of the original “British Coach Works” in East Acton.