There are only a handful of copies exist of each, perhaps no more than 5-10 copies in any condition.
Comic Book Postal auctions sold a Fine copy of #6 for £969 in their Spiring 2010 catalogue.
Jun 2015: Comic Book Postal Auctions sold a VG copy descibed as 'Good cover colours, one inch horizontal spine tear going through all (light tan) pages. Some back cover margin foxing' for £1459 in a 14% Buyer's Premium. Early Beano prices are on the move!
2016-2020: early Beanos have seen continued healthy sales thanks largely to the continuing work of Comic Book Postal Auctions and Malcolm Phillips. Well done sir!