Leaded or unleaded?

I have been ill all week with a flu like lurgy but wobbled out today for the first time since last Sunday.

It turns out I find roofing quite interesting and stopped to have a closer look at this leaded section on a church roof. Our building has a section a bit like this except Messers Bodgit and Run came up with the brilliant time and money saving idea of pouring a line of concrete or similar down this bit instead of leading it properly so that rainwater just pours straight in at the join. It's a good job the electrics are right underneath. Oh no wait..