After a service at Stevenage Mercedes, the engine light came on. I called the RAC who told me that the dealer didn't plug the EGR valve in correctly. I contacted the Service manager about this and he denied everything and said it wasn't them? Then on another service the technician damaged my antifreeze cap, it was over tightened and stuck, then it started to leak. That's the last time I went back, they can't even do a simple job. They also kept me waiting for ages and spent most of their time talking to each other than looking after their customers. I complained to head office, see if they get their act together! Very Poor!