Another one that needs a helping hand.
To summarise what we know so far -
British (all elements), Austin-Healey body, 'one-off' built by an individual.
I'm going to award more points now - one for the basis of the car - marque and model (it may have a specially built chassis but the running gear was from a British prewar car)
and another point for the make and size of the British engine it used.
It is believed the car was built in the mid-1950s by a Mr. xxx (possibly another point for the correct answer to that)