My rental company was Green Motion, not Carnect. The car was good, a Korean make. I originally booked a Volkswagen Golf, but they gave me the Korean car instead. This car might be more advanced than the Volkswagen Golf, making it easier to drive and more comfortable to ride in. Many roads in the UK are narrow, and its lane departure warning system was very useful for those of us not used to driving on the left. Additionally, Green Motion's pick-up and drop-off procedures were convenient, and the staff's service attitude was good.

1. The reception told me that a petrol version car could only go 200 miles on a full tank, whereas a diesel one could go 500 miles. They persuaded me to upgrade to diesel for 60 Euros. When I got to the parking lot, the staff handed me a beat-up 9-seater Volkswagen diesel. I said I had chosen a Mercedes, but they told me that was the only car available in the same class. I was scammed out of 60 Euros. The fuel cap of this car was broken, and it wouldn't close properly. Throughout my trip, many kind locals tried to warn me in various ways, including making me pull over on the highway. 2. Upon returning the car, I was told that I would be charged extra for exceeding 100 miles per day, which was not mentioned during the rental process. Luckily, I had a Chinese friend from the UK with me, and the staff waived the fee.

Tried to sell more insurance coverage with big big push. Made customer to take specific photos and videos of car before start of use. Did not give any signee paper after return.

Booking was easy

Cars always exceed expectations, full option, clean great car, very long queue due to bank holiday which is understandable, people at the counter were friendly but of course they have to try to sell insurance, just make sure you know exactly what you want when you get there and you won't get more offers.

Like: We didn't have to wait in line, either for pickup or drop off. The price of the rental was very reasonable. We were given a free upgrade to a larger yet still fuel efficient vehicle, and the car had GPS, which would have cost us substantially more than the total price of the rental if we had to pay for it.
Dislike: Although you can pick up or drop off your car between 06:00 and 22:00 at their Heathrow Airport location, you can only call them (or any other Green Motion office) between 09:00 and 17:00. Also, we had to pay 9 pounds each for my wife and me to ride the Hoppa Bus from Heathrow to Green Motion and back again. While the car rental broker company, EasyRent, said that we would not be reimbursed for this fee, the supplier, Green Motion, said that we would, and we have not yet resolved this issue.