Donington makes it pre-war.
The 1936 GP had fourERAs in it:
#8 Whitehead
#14 Briault
#15 Tongue
#16 A Dobson
See this summary:
http://www.kolumbus.fi/leif.snellman/gp366.htm#37
Photo 1 is of #14
Photo 2 is of #16 and the garage confirms the name.
However the garage numbers in 1 don't tally with photo 1.
If it is '36 then #2 is Cholmondley-Tapper's Maserati and #18(?) is Bira's Maserati.
However I am sure someone who actually knows something can confirm/deny and fill in all the details.