Well I don't think its an AC, a Lea Francis a Wolseley or a Fraser Nash, even a Rover.
Whats left, Caterham?
Lorry, you were so close, a bit more research you would have hit it on the nail.
Firefly, You got the right angle there mate.
So Mr. Z, have you as the font of all knowledge of classic vehicles got it yet?'
Read the clues, part of the answer is in the first clue.
As an aside, 'racing' was not part of the question or a direct clue although the photo was taken at Brooklands. So I think your recent remark was unfounded.
Combine all the clues, you should at least get near.