Marcel's and my posts have crossed each other, so more clarity is needed.
The picture shown by Marcel is an artist's impression. The picture published in Four Small Wheels for March 1977 is of an actual model of a finished 'Fire Engine' and Jaguar.
I can show the picture (below), of the Rolls-Royce and you can see it is of very low quality, as was the whole magazine from this period...

- March 1977 picture.jpg (93.54 KiB) Viewed 2188 times
The Jaguar would have shown up as the same quality, but as I mentioned earlier, my notes from this time say it was Ivory (difficult to tell from the image, so maybe there was a description of the colour with the image), and one Day I will find it.
GHOSTHUNTER.