I had a siimilar issue with MB Chester. I just called back and spoke to someone else, who knew I'd spoken to her colleague the day before and transferred me to her, which was slightly awkward!
The trouble with MB Chester, and perhaps all dealers are the same, is that you're talking to a "service booker" - they don't seem to know anything or have any ability to negotiate. I had a target price in mind which another forum member had been kind enough to share with me when he had the same work done a few months earlier. They did go back and forth and eventually came back with a decent price, and the promise to review it further when I came in.
The actual service advisor who dealt with me when I went in was more switched on, but he had to trott back and forth the service manager to agree the price and they did knock a further £30 (I think) off. Interestingly, they thought the target price I was giving them was from an indie, and they said they would try and compete. They didn't seem to realise, despite being told, that the pricing was something THEY had charged a previous customer.
How old is your car, by the way? Seems they're usually very reluctant to discount on cars under warranty and they think they've got you by the short & curlies.
