I've picked up a small but deep stonechip on the leading edge of my roof just above the windscreen on my 300. The paintwork around seems to be beginning to bubble in that rusty kind of way anyone think it woth trying to get this sorted under warranty?

Definately, the paintwork is renouned for its ease of scratching etc, worth ask your dealer to submit a warranty claim and see what happens.

If you don't ask you don't get

Kwack

they will pull the old external damage not covered tofee out of the bag.paintwork warranty only ever covers faults from under the paintwork and at this point its hard to prove anyway.