Isn't Game the UK version of Gamestop? If so they would be getting their deliveries likely through LTL carrier rather than what I'd assume to be the UK version of the post office. Additionally, Amazon in the states uses UPS or FedEx for deliveries. So it's odd to me that they would be affected at all by the strike but then again I don't really know how things work across the pond.
Amazon use Royal Mail for the vast majority of game sales, as the parcels are small. You CAN choose express delivery for which they use couriers, but you cant choose this option on pre orders. I contacted them and asked. All the GTA games where sent RM, and loads where held up in transit.
Game is the UK version of Gamestop I believe, and they ise RM too.
Theres 2 options for buyers regarding outlets to get a pre order and avoid the strikes.
365games.co.uk, and choose UPS or Royal Mail special delivery , they`ll both get thru
shopto.net, and choose DPD courier, theyre very good and will get there the day of release, they also email you to say what time they`ll deliver, within a 1 hour slot