I guess i misunderstood the entire process, and my husband just set me straight. (this is all very confusing to me....)
after reading the rule on the PETS website (fact sheet # 4 in particular), like WebyJ referred to, we have had her micro-chipped, vaccinated against rabies, and blood tested (in that order with appropriate documentation). Our understanding (and our vets's) is that 6 calender months after that successful blood test she can enter the UK... What happened to bookgrl's friend is that a dog in the UK does not need to maintain their vaccination record. A dog entering the UK does. The rule is that a dog (well, her owners) needs to be able to prove that she is micro-chipped, vaccinated, and blood tested (and passed), and that since then she has received vaccine boosters before the previous vaccine or booster has expired, in order to enter or re-enter the UK. All of this information goes in to the pet passport or health certificate.
For us, Zoe was tested (and passed with flying colors!) on 6 August, so she can get in on February 6. The point of going to France is a different complication. The pet must also follow an approved route in to the country. From the US, all of the routes force the pet to fly in checked baggage. France does not have this rule. She can fly in the cabin to France. Air France says there can be up to six pets in the cabin on each flight on the route from Boston to Paris, so we have to check her in after reserving our tickets. The pet and the bag she is in must be less than 6kg (about 13 pounds, Zoe is a bit more than 7 now) and the bag must fit under the seat.
The really complicated part, it seems, is that the certificate of health issued from a third country (not an EU pet passport) is only good for four months... so you need to time that appropriately in terms of when you get it filled out.
Thanks for all the advise and help everyone!! This whole process is very confusing.
Best,
Alison