We had to do Leadwork at College as part of the City & Guilds Plumbing Course, circa 1990. I wasn't very good at it to say the least, think it needed more patience than I could offer it! My Gaffer at the time didn't do it, and said the Roofers were taking over.That's a really specialised job. Traditionally done by the plumber, but nowadays leadwork has become a separate trade, as a lot of plumbers had no interest in taking on leadwork.
I know a Lad who does purely Leadwork now, he's annoying, partly because he makes it look so easy and partly because he is rather bloody good at what he does.