As far as I'm concerned, the only way the "two cells containing single digit numbers" gimmick works, is if you write out in letters the words required at those locations. For those entering their grids for the weekly competition, it would be only fair to accept EITHER numbers OR words in those cells. Furthermore, if I was really "going postal" and sending my grid in an envelope with a stamp, I don't think the postie would be too keen on what I think should be entered in the bottom three cells of the far right hand column, unless he is suitably classicaly educated. It certainly can't be NELSON. Are we wandering into territory that might be termed "unfair"?