...as a trial for this as a marketplace for these, it was a costly lesson but at least I can be fairly confident this board no longer has the reach (in terms of proportion of potential buyers) that it used to and seems to be mainly dealers who pay 'trade' prices.
Had this gone well, the next on the list would have been the first of the Cas silver-gilt tens but I won't risk a repeat of this disappointment x10 and will now need to thoroughly research other options.
It has been funny coming back here after the years away (after Theymos's many shenanigans and the blocksize malarkey) and kind-of apt that it has ended with disillusionment again. Ah well, such is life. Wishing you all the best.tf