The Royal Mail Olympic Stamp pins arrived today, so here's an update.
As mentioned previously, each pin is presented with the matching stamp on a card. The stamp is held in a type of blister pack which exactly fits it, so the stamp does not move.
The card measures 8cm x 10cm and carries the London 2012 brand and logo. The top left of the card contains the name of the collection, the bottom left, the name of the sport and the bottom right the number of the pack in the series.