My car failed its MOT today and one of the things was corrosion around the rear right jacking point. After a bit of poking and a quick go with the wire wheel on the grinder it turns out the rear few inches of the sill was complete rust. I've cut out the offending rusted part, which is a good 15cm of the sill from the back, and some of the structure behind it including the thicker bit for the jacking point.
I've now got to decide what to do next. Could I fabricate some metal to replace the parts I've cut out, or do I replace the whole sill? While I have got a welder, I'm very out of practice and don't want to do more than necessary. How easy is it to remove the whole sill cleanly so a new one can be refitted?
Do mobile bodywork welders exist, who can come out and do such jobs?