It's been a little while since we moved our dogs back to the US but as far as paperwork it was really, really easy. At the time the airline required a fit to fly letter from the vet and we took their vaccine records. I don't recall anyone ever really looking at anything. WE collected them from the baggage claim area in the US , took them across the area to what I think was the USDA type office, the agent asked where they came from and as soon as they said the UK they said "oh you're fine, and that was it. We walked them through customs with the rest of our bags. There also was nothing about the 6 months but then again they've always had a current vaccine so I might have ignored that part knowing it wasn't a problem.
