We bought, from Mercedes Benz of Salisbury a 2004/54 CLK 320 Coupe Avantgard with auto, leather, comfort pack, audio 10 plus CD changer and phone pre-wire, etc, etc. 30,000 miles, one previous owner, and paid £17k including a 1 year MB Warranty and 2 years labour free servicing. Before signing the order I made it clear the car needed new rear rubber. They said “ok”. We picked it up a month ago, immaculate, new rear tyres. After 500 miles on wet roads the ESP light was flashing almost every time I pulled away, even in “C” setting so I had a look at the tyres. The dealer had fitted something called Accelera, made in the Philippines and on the web at about £55 each. I complained. The dealer said they are fine, we always fit them. The handbook says to only fit recommended tyres otherwise ABS, ESP, Traction control all may not function optimally. A letter, on the lines you described, sent on Sunday to the dealer and copied to Mercedes Benz Customer service, led to an immediate response from the dealer and by the end of Tuesday the car had new rear tyres of the same make and model as those on the front. (Michelin Pilot Primacy SP2). Thanks again for your help.