After reading this post I was filled with optimism, for I too got a good deal on my M800 a couple of weeks ago and feared a huge first service bill.
As it turns out I was not disappointed. Just got off the phone, they are trying to charge me £215
I reminded them that I actually bought the bike from them and I know for a fact that they just serviced an S4 for well under what they were quoting me.
They said that the S4 owner must have negotiated a deal with the salesman at the time of purchase and the 1st service takes over 4 1/2 hours so they can't budge on the price.
I told them that Italsport would do it for £150 (and would have done it for next to nothing if I had bought the bike from them), and they simply said sorry it's still £215.
It's safe to say that they have lost my custom for anything but warranty work in the future....
Macca