I own a Mercedes-Benz E43 AMG, registered in 2017 with 10,800 miles on the clock. I booked it in for a service yesterday and was quoted £850. Part of the service had to include replacing the spark plugs. I was told if I did not replace the spark plugs, my cover would be withdrawn (car is still under warranty until the end of May). I've owned cars before and they only replaced what was necessary and always reflected the low mileage I do - 5000 miles a year. Mercedes-Benz also offered me a two year service contract for £42 a month, is this a good idea? I feel I am being fleeced and would appreciate your comments.