Extension leak

[chillipast]

Hello!

I woke up to find some water ingress in my single-storey extension, just past the door, where the extension meets the house. Any clue what may be the cause? Pointing looks generally okay, there's some tiny holes (circled in one of the pic) but I'm not sure that's enough to cause it??

 

[ree]

OP,
Good practice for pitched roof additions is to install Cavity Tray Type-X flashings - do you have any kind of cavity tray?
1. Is that, what looks like, a felt support tray above the gutter?
2. The bottom edge of the flashing could be welted up and/or a Kick-out installed?
3. Lift the step-cover flashing & look for water penetration. Check the lead turn into the chase is a secure min of, say, 20mm. Check the saddle goes under the ridge tile.
4. Could you post a pic looking down into the LH end of the gutter?
5. Standing on a ladder you could sprinkle water test the flashing - starting at the gutter & going up to the ridge? If you have access to the addition roof space then someone could check things from inside the roof?