I do not have after photos and yes these are the photos before any work was done to my side but several years after his builder did the job. There doesn't seem to be any strip of any material to seal my side. To me it looks like the neighbour did nothing to seal in the join as I don't see any new felt or material anywhere just the new upstand. As I understand it the builder acting for me basically torched felt onto the upstand and down onto my roof to seal the gap that is showing in the pictures. I am being told that there was nothing to stop water going straight into that gap and then into my ceiling space. I am just baffled as to why a roofing company would make this sort of error if it is true.
It is watertight now it seems but I am waiting for it to rain....I still am uncertain about what I am looking at to be fair. I would have expected to see some new felt on my side where they have ensured the job is watertight. But that's why I'm here I'm hoping someone can clarify for me.