I was told yesterday about someone who had hired a car in England recently and when the car was collected the company's policy on fuel.
The renter was told to ensure that it was filled up with fuel within five miles of the car rental company and the receipt being shown to the company on return, otherwise the hirer would be breaking the law.
There is probably no law in England and Wales that actually says that, however if someone does no of a law please contact us where it is. I believe the car hire company really was stating company policy that as a condition of hire they need proof that the car has been properly re-filled and more importantly with the correct fuel.
It is very easy if it is not your car to accidentally put in unleaded fuel into a diesel car and vica versa. Most rental car will have the appropriate sticker near the fuel filler cap and putting the wrong fuel in can seriously damage the vehicle.
If you collect a car with a full tank of fuel and the arrangement is that you return it full, it needs to be full. You certainly need to do this at the nearest petrol / diesel location to the car hire depot (or motorhome or van or truck).
Sometimes it can be rather difficult, particularly if it is a new location or dark. Last May I had to return a car to the Paphos Airport in Cyprus. There might be a fuel station on the airport site, however fortunately I was following friends who actually had to return their car empty (because of the hire arrangement they had), but knew I had to fill up my vehicle. They were regular visitors to that area and knew of a filling station just before reaching the airport. Had I not found anywhere I would have had to get the car hire company to fill it for me and pay the charge.
It is advisable to keep your fuel receipts to prove that you have filled the car up before returning it If there was any problems of being charged for re-fuelling the vehicle and having a deduction made on your credit card, you can at least prove it to the car hire company that you did in fact fill it up.
You should keep these receipts for a few months after the hire in case of problems.