Having done a little further research, I think I can say with confidence that Nos 1 & 3 above, are in fact the same coin. I've compared and contrasted the Colin Cooke pic, with the smaller black and white pic in the Christie's auction catalogue from 1984, and the light marks round the left of the O of ONE on the reverse, as well as the mark just above and to the right of the N of ONE, also on the reverse, are identical.
Although the Christies pic is not brilliant, the marks in question show up quite clearly under a magnifier.
So the total above is reduced by one, to five