This is a very rare item that many collectors may not even be aware of. In 1989 a short-lived Corgi Premier Collection was proposed with models being produced in pewter in limited numbers.
I don't know whether anything else made it to the market but these were available on mail order and only 800 were produced. They are, as you can see from the comparison photos, manufactured using the original Corgi casting, most likely the 1985 version of the 1965 one that had, a little earlier, produced the C861 Classics model. It is quite remarkable piece of engineering, with even the seats and hood (and bizarrely the windscreen) produced in pewter. The wheels also turn freely which does add to the models attraction although I think i would have preferred rubber tyres and a perspex screen!
These are extremely hard to find now and difficult to value. This is, however, totally original, in superb condition and will look fantastic in any cabinet!