Lead Gully leaking

[chivers67]

So i went to my mothers yesterday three hour drive from Surrey to Shropshire and had as look at the leaking Lead box Gully on her disastrous extension, I've previously posted on here about it but hard to get involved when we have three kids and my wife and I work full-time etc.... I've attached some photos and a video. I don't think the lead rises high enough and water is simply dripping through in a couple of places from what I can see and the lead seems to run down and stop and go under a tile at the very end, i'm no roofer but it just doesn't look right. I'm not sure the best cause of action, I'll probably have to get another roofer to look at it (this will be the third person to work on the roof) after my sister has had two very bad experiences now.

I Can appreciate it's difficult to know exactly what's going on here but any advice welcome.
https://www.flickr.com/photos/chivs/23824140556/in/dateposted-public/ hope the Video link works

Chivers

 

[catlad]

were is the water supposed to leave the roof

 

[chivers67]

This is at the end of the "box gutter" the water goes through a small gap under the tile, it was full of dirt/debris which i cleared earlier today but I was thinking of taking this tile off and cutting the left hand bottom corner. Next time i go up after Christmas to help water flow out but looks pretty shoddy.

 

[catlad]

Wow! what can I say but of course trim the tile to let the water out.