Personally I wouldn't bother! Phone your local cab firm and find out what they charge for a return trip. Who wants to drive home after a long flight? Plus it might work out cheaper
In March my wife and I booked into the Heathrow Novotel Hotel for overnight stay prior to morning flight to New York. Five days parking for our car, and a "day room" (9am to 6pm) on the day we came back. The day room was great as we were able to shower and rest before driving home.
Total cost �180. The day room part of it was �50. We considered it money well spent.