The first South African car, built by Vic Cavanagh in early 1947. It got it's name from a tendency for the rear mounted Sunbeam engine to bend the back axle! Front suspension was Fiat and the rear had a very narrow track and almost no suspension. As a result, it had a tendency to roll......

A very similar Mk II version was built later in '47

Extreme crab track well illustrated here.

Vic clearly had a sense of perspective about his creation as his letter to Iota in February '48 shows:

Update from Rob Young, 29Jan2017:

I came across a report on the 1948 Leeukop Hillclimb in South Africa on 21st Feb that year. Extract below -
The 500-c.c. Cavanagh Special ran, but had a lot of trouble (it is the first "500" to be built in South Africa, I believe). Its owner, builder, entrant mid driver has put a Sunbeam "90" motor-cycle engine in a F.I.A.T. 500 chassis with i.f.s. Interesting features are the engine placed behind the driver (the only one of this type at the meeting) and its very narrow track rear axle. Unfortunately, no times were recorded for this interesting vehicle. In this instance and also in the case of a few others, I believe the electrical timing apparatus was at fault. A pity as it would have afforded a comparison with larger cars, particularly in view of the interest this class has aroused in England. Though perhaps because of its stubbornness it is just as well its times went unrecorded! Interestingly Leeukop (Lion’s Head) is on the border of the Kyalami circuit and the bend leading into the main straight was called Leeukp. An uphill right hander. Leeukop was also the site of a prison.

If anyone has any more details or photos of this car, please get in touch.