I had a bump repaired cheaply a couple of years ago, stupid I know, and now a serious looking bubble or two have appeared on the top of the arch. Further inspection reveals a fair amount of corrosion in both the rear sills too, not all of it can be down to the knock I had fixed as it was minor and only on one side. I am assuming that there must be a lot more that I cannot see. Any advice on where to get it all done, near Bath, and the sort of costs I am looking at?

Simon