Oh, that's easy really.
You ask them to bring them in and you take them all home and scan them.
As you know, I work at the Clermont so...better placed than most to try to find them all.
It also helps when they ask you to try to sell them for them too, I suppose.
Still not found anybody with the full set of 5 (of the 18 sets given out) and nobody knows anybody with a full set either so.....
Still on the lookout for the £100,000 whcih I know at least exists, here's hoping.