Leaking Metal Chimney Stack

[I'll have a go]

Hi, we had a new roof fitted five months ago (left side roof). Around the seam area of the circular chimney stack (see image 1) water is leaking into the roof. We've asked another roofer to take a look at it from the outside and he says the original installer has fitted the chimney incorrectly/the wrong way round? Not sure if he means the lead/tiles or collar? I didn't understand his explanation. From image 2, could anybody explain what the problems may be and why water is getting into the roof. Many thanks in advance for any advice.

 

[Alastairreid]

Most likely culprit is the rubber seal on the lead slate been cut badly and not sealing.
The adaptor connecting the twin wall does look the wrong way round but that would need checked by a qualified gas bod.

 

[I'll have a go]

Thanks for the info. Will follow it up.

 

[datarebal]

The additional slip of lead is to short . Some water could track sideways .
It would have been better I'd a lead slate had been used with the appropriate collar.
The rubber may not be sealing the pipe where the pipe seam is .
The ridge is a mess there could even be water tracking down from there
There are a few possibles there .

And get the internals checked as above

 

[I'll have a go]

Thanks for the detailing of the issues. Will get it looked at. I thought initially that this was a good neat job but now it appears to be a rush corner cutting job to make more profit. Hopefully the issues can be resolved without too much new costs.