Need to go through the rigmarole of contacting a roofer. (The one I used 2 months ago (took £1,200 pounds from me too) has had two chances to come and quote, but after another week of no show, I've had enough).
Clearly the valley needs to be put straight. The lead flashing was replaced 4 years ago, and looks grand. It's just the mortaring of the tiles that seems to be the issue.
Is there any more modern system cf the ridge tile system I had fitted, where the tiles are held in with plastic clips which are screwed into a batten with a waterproof skirt underneath them ?
Mortar seems to be the worst idea ever IMHO. If anyone wants to reply and say that it's the best thing since sliced bread, as long as it's done properly, then it's still shite as over the past 12 years, I've had 4 roofers mortar the ridge tiles, and it only seems to last 3 years.