Like the other complaint about Amigo Autos the other company involved was Goldcar.

Dispite their written terms they have now decided to enhance their profits by excessively charging for the tank of fuel and then saying even on a short hire the car can't be returned full. Thereby forcing you to use their fuel, for which they charge twicw as much as it would cost you to fill the tank. They threaten if the car is returned full to charge you for the mileage used.
I will be avoiding them and would suggest their are plenty of companies who don't try to rip you off for us all to use in the future.

I booked a hire car for 2 days in December 2008 with this company over the internet. I gave my credit card details to someone (I now believe they were in a call center, possibly not in the UK at all) I was met at Heathrow, by a friendly individual called Terry, who took us to the car in the airport carpark. We dropped the car off the following evening in a London Hotel. Terry met us there and took the car - there were no problems with the car. When I got home I saw that my credit card had been overcharged.. The quotation was 131 pounds and my card had been charged 810. I made numerous phone calls, sent emails, even registered letters. The phone system kept me in a queue for over 30 mins and on the two occasions that I spoke to someone, the cut off the call when I explained the situation. I have now sent all the details to HSBC Visa card disputes department and they are investigating.

There are several other reports on the internet of exactly the same situation occurring. I am not going to let this matter drop. If anyone has managed to resolve a similar case, please let me know. Thanks!