Leak on roof close to velux

[wildember]

Hi all, we have a small extension with pitched roof and 2 velux windows. Next to one of the velux windows, in heavy rain, we get a linear patch of wet coming through. It has done this since installation.
Any ideas where this water would be coming in from - the velux or somewhere else above?
I've attached some pictures mid installation of a new flashing kit which we hoped would fix the issue. Thanks for reading!

 

[datarebal]

Velux could have been a bit lower down the roof . They are shy on front apron lap . It's a low pitch..
Also, check around the window and the lead flashing lap above.
And the tiles and batten are not fitted correctly .

 

[noseall]

Velux could have been a bit lower down the roof .

I thought that, looking at the bottom apron in relation to the tiles. It's as if they have ignored the first page of the fitting instructions.

 

[wildember]

Thank you both very much for the pointers to get started on!