We booked a vehicle through Enterprise rent a car, with pickup from Heathrow on 20 Sep 2017, through until morning of 12 Oct 17. We had booked a medium sedan. First our quoted price was exactly what we were asked to pay, other than cost of a full tank of fuel which I elected to pay for rather than worry about how much fuel was in vehicle on return. We had booked the vehicle in automatic and with GPS. After a few minutes completing the admin arrangements, the customer service rep advised there were few auto's available and said would be fine we could have a FREE upgrade. We walked to the car she selected and were loading our bags when she found that someone had hit a gutter and taken a piece of rubber out of the tyre, and then said well you can't take that one. That's OK she said I will have to give you ANOTHER free upgrade. We then proceeded to a near new Nissan Qashqai SUV and drive off pretty happy. Our return of the vehicle went very smoothly, and we caught the shuttle bus to the International Terminal. We have all seen horror stories about car rentals gone wrong, on this ocassional we could not have been happier.