Well I think it may be the car modified post-war (1948) as a Formula B single-seater by St John Horsfall.
Inman Hunter tells us that it developed 125 b.h.p. with four Amal carbs. and dope fuel and was able to achieve 140 m.p.h.. It was later road-equipped to run in the Spa 24 hour race.
Looks like this now (and has done for half a century):
Yes Allan that's the car.
Chassis no. J6/707/U, originally a Speed Model, had been raced by Rolt and Talbot in 1938 and 1939 prior to Jock Horsfall acquiring the car and converting it to a Formula B single seater in 1948. After a year competing in sprints the car was converted for sports car racing and was driven by Horsfall in the Spa 24 hour race. Remarkably he drove single-handed for 24 hours finishing 4th. overall behind a Ferrari.
Sadly Jock Horsfall was killed six weeks later whilst driving Peter Bell's ERA at Silverstone.
The car eventually passed into the hands of the Freeman family in 1955 who have campaigned the car with great success ever since.
Another two views from the late Inman Hunter's book on pre-war Astons -
First is a front view of the car as a Formula B in 1948 and the second after it had been converted to a sports racing car for the 1949 Spa 24-Hour Race.