This second car is chassis number 31413, a 1927 four-cylinder that was known relatively recently to be in South Africa (and likely still exists there?)
There are similarities between both cars in the photos, which make me wonder if they are, in reality, the same car? Even though the museum show 1924 for their car, and for the second the ACOC show 1927 (and this is correct).
For example, both show the same-type wire wheels, not discs, and both have unusual bolt-on side windows, which move and probably extend also. Also strange, having the spare wheel on the left front wing, not right, (the first car shows no wheel-well on the right wing). It would be most unusual for a 1924 four-cylinder to have front-wheel brakes, unless fitted at a later date (though some wire-wheels did have fake ‘drums’). So, some coincidental similarities?
In some countries the registration number is changed when re-taxing/licencing the vehicle, which I think happens in South Africa (the recent 1928 2-door saloon that was for sale now sports a different S.A. number plate to a few years back).
If the photos above are the same car then it would seem to have unfortunately deteriorated.
PS Notice lack of tyre tread on TJ 121920!