good car, bad service

I have used Green Motion a number of times and have always had a good experience bar picking up the car which always seems to take a while. However during this rental period I was left feeling very disappointed and angry with Green Motion. Upon leaving the car, I was told it was too dirty (I had used the car on a couple of country roads and the motorway) and as it’s winter and it has been raining there is dirt on the roads so the car had mud splashes and mud debris from the pushchair inside the car. I was told that due to this the car would need to be valeted at a cost of £96. I had a flight to catch so could not take the car to clean it myself. Had I been made aware that the car needs to be returned clean, I would have cleaned it myself. Never have I been told that a car I have used is too dirty. I was gob smacked and pissed off at the charge. So much so that I will not use this company again.