BA World Cargo and the staff at the Animal Reception Centre at Gatwick both required me to present an APHIS 7001 certificate that had been signed and sealed/endorsed by a USDA vet - the former in order to accept my cats for shipping and the latter in order to release my cats to me after arrival. This was in October 2006.
I don't know if the date on the certificate must be within 10 days of flying or not - mine was, my cats were processed, so I had no reason to worry. I do remember calling the USDA vet's office in Conyers, Georgia in early September 2006 and being told that I could not schedule an appointment that fell any earlier than ten days prior to departure. I can't imagine why they would have said this if the ten-day rule did not apply, but I can't know for sure!
As with any other PETS issue, I advocate the "better safe than sorry" concept - you are of course free to do things any way you like, but I will always advise those who post to this board to cover all bases, even those that they may have been told (by professionals in the US and/or the UK) aren't necessary. It's a lot easier than fixing a problem on the day of departure!