I wanted to post a follow-up in case anyone Googles this, like I was doing. What I discovered is that it’s possible to take a dog into the UK as long as a lot of hoops are jumped through. I can’t remember exactly what, but it was along the lines of ISO microchip, rabies shot, rabies blood test within a couple of weeks of departure, health certificate, flea/tick medicine, deworming, etc. The problem was that the UK has very strict rules regarding rabies, so even though I could get the dog to the UK, they had a regulation stating he would have to stay in the UK for 3 weeks prior to being allowed to travel to another EU country.
That meant that suddenly, I was going to Italy for the summer, as I would be able to book a direct flight to Italy, thereby only dealing with one country’s pet import regulations. I found that most airlines have restrictions on when pets can travel in cargo. Some go by date (such as Delta, the cutoff was May 15), others by temperature at the start, stops, and destination of the plane (American, max temp is 85 F). I booked with American, who allowed me to take the dog in the cabin for the SF to JFK leg, and then I checked him as cargo for the JFK to Milan leg. Fortunately, the weather cooperated and all went way more smoothly than I’d anticipated.
Ultimately, what I had to do to get the dog into Italy is: ISO microchip, current rabies shot, health certificate (Italian pet import health certificate downloaded from the consul site) both filled out by the vet and then taken to a local USDA office to have stamped by a USDA vet. To be safe, the dog was given a dewormer and flea and tick medicine (also noted on the health certificate). The airline had to be notified in advance that I was traveling with a pet, and it cost $100 from SF to NY, $150 from NY to Milan.
Once I got there, he was deposited in the baggage area and I was waved through Customs (the sole agent was busy chatting with someone, God, I love Italy!). After all the worry and preparations and more worry, it was pretty much anti-climactic. The puppy arrived safely, has settled right into village life, and is a pretty contended little pooch. :)