I have hired from Green motion at Stansted and Bristol and I have been most satisfied with both. The vehicle at Stansted was under powered for my liking but that was my only complaint. If you follow the format you shouldn't have a problem, ie the right documents etc. These days it seems its so easy to blame the other person and read reviews that put you of using this company. Someone in the transfer vehicle had been using green motion for six years twice a year and spoke highly of them yet just before I booked I had read a review which absolutely slated green motion but I chose to ignore it and booked anyway and had no complaints other than I had some difficulty locating the transfer pick up point, now I know it it's simple and more convenient than going to the on site rental companies. Turn left outside of the airport and walk 50 metres under cover to the pick up point and wait for a Mercedes people carrier with their logo on it to take you a short drive to their office, simple! Great car, clean, all efficient.