Moffmo

I think you're right as there's paperwork for previous rust repair. Whoever paid for it got shafted! Somehow this rust past its last WOF just before I bought it...

The rust in question.

If this is the case, that would be a cut and weld job?

My van has loads of rust on the side of the roof, it's surface rust that has bubbled up through the paint. I'll post some pictures up later. A lot of the advice on here has been about rust removal on parts that are able to be removed from the car. Would it be possible to wire brush this down and use the acid and then reprotect/paint this?