^^ Yep, despite the sign saying that the wait could be 4+ hours, we were in and out in about an hour. We flew with the cats. The plane landed, we took a taxi to the ARC @ Heathrow and less than an hour after arrival at the ARC, we were in a minicab on the way to our apartment. It was shockingly quick. There was another pet on our flight, but our cats were processed first.
Good luck!