Looks like the T-circuit at Caversham, with broken off brushwood down the centre of the airstrip to separate eastbound from westbound traffic. There were very few T circuit meetings - 2 or 3 only, I think - which makes these very rare photos.
Caversham consisted of a north-south runway, with a dispersals road off to the east - the "D circuit" - plus two additional long runways to the West linking to the north and south ends of the main runway, sort of like this: XD. Thus you could have 3 circuits - the D to the right, a triangle to the left, and a T at the junction of the diagonal runways. All three were used, the T and the Triangle only rarely.
The Healey in the first photo has a Northam number plate and is probably Fred de Bonde. The Healey in the other pic has numberplate 212, which makes the driver Aub Melrose.
Ken Devine's historic racing photo displays attract enormous attention, with the result that he gets remarks like this:
"You know, I've got some old slides somewhere I took of car racing at Narrogin . . . would they be any good to you?"
You can fill in your own reply. The pics I've been posting up for Ken lately are from two such encounters. My role has been mainly scanning and posting.