As far as I understand, dogs are still not allowed in the cabin to fly into the UK (unless anyone has experience to the contrary) so we were planning on flying from New York to Paris on AF (as they allow small dogs in cabin), before hiring a car and driving back to the UK via the Eurotunnel.
Exactly. And that's a good plan.
In terms of flying back to the US, it seems the regulations flying ex-UK are a little looser, and as long as the airline allows it, anecdotal evidence seems to suggest dogs are apparently allowed to fly in the cabin ex-UK... but I can't find official confirmation. Does anyone have any experience of this?
The regulations might be looser, yes. But the point here is "as long as the airline allows it" - and no airline flying directly between the UK and the US (AA, BA, DL, VS, UA) allows pets in the cabin on the routes ex-UK in any class of service. I believe that the airlines simply haven't updated their policies after the UK government relaxed regulations recently.
You would need to connect in mainland Europe as on the way there. Just buy a return ticket via CDG. That will turn out cheaper, anyway - one-way car rentals to London form Paris are prohibitively expensive. Just be aware that driving on the left in the UK with a LHD rental car is a bit more of a challenge
Finally: a lot of the UK government literature makes reference to needing an EU pet passport. Obviously this is not possible with a dog based in the US, so what sort of documentation do I need? As far as I can tell, as the US is a UK approved 'listed' country I just need a 'third country official veterinary certificate' filled in by a US vet.
Is this about right? Any advice or experience in navigating this maze would be most helpful.
Yes, that's about right. The requirements are listed here in a pretty concise manner:
https://www.gov.uk/pet-travel-inform...for-pet-owners.
Print out
this certificate form and have it completed by an official veterinarian (contact
your state's veterinary services office for a list).
The Eurotunnel car shuttle (NOT the Eurostar passenger train service! No pets on the passenger trains!) is an approved route under the pet travel scheme. You need to but a ticket for the pet and are supposed to go through a pet control check at Customs, though - details
here.