Had rust bubbles on the wheel arch flanges on my SLK 230, not too bad on the fronts, but worse on the rears. I thought I would catch it early and get them done proffessionally and on the reccommendation of Peter of this forum, took the car to Vanleigh in West Molesey. They did a super job for the grand total of £600.00.
I can reccommend them if you are within a reasonable distance.