Obviously this suggestion will be too late for you on this occasion, but I recently spent some time trawling the net to find an alternative to the RAC for my European Breakdown cover and found this;http://www.motoringassist.com/breakdown ... own-cover/
Gem have a good reputation in the UK for their breakdown cover and I was interested to find out about their European policy.
I made some enquiries and the quote was very favourable. The breakdown assistance is provided in Europe by Mondial, who I understand provide breakdown cover for Mercedes and BMW on the continent.
I also got a quote from Green Flag, who were slightly cheaper than the RAC, but with a much reduced level of financial cover in the event of a problem resulting in your car being off the road.
In the end, I stuck with the RAC, who on one occasion repatriated my car from France, due to accident damage and provided me with a hire car for the duration of the holiday and right back home, where my own insurers provided a courtesy car whilst my car was repaired. Having experienced the level of service they provided, I find it hard to place my trust elsewhere.
Have a good trip!!!!