If Nokia delay supply to Third party retailers like Play and Amazon till Christmas, they may well find themselves in a nasty spot. They can afford to lose my goodwill. Not so sure they can afford to lose Amazon's.

Besides which, the original date which Nokia gave Amazon was 26th October - exactly the same as their own release. Why change policy now?

I suspect what you have heard is that the shops, places like Carphone Warehouse and such, will be getting it a bit later. From what I understand, that's pretty normal.