Water leak location covered by Roof Guarantee?


In March last year I had the roof of my rented house I bought 10 years ago redone for £4500. The tenants had complained about damp, and a handyman had said that the roof was in bad state. I asked for a few quotes and went with one below where the builder gave a 10 year guarantee.

However, the new tenants have said there is still damp, and with the help of the neighbors we found that it looks like the water ingress is coming from the location shown in the picture. We suspect this is the culprit as the ceiling and wall of the bedroom in the corner has the most noticeable damp.

Would the work that needs to be done be covered by the guarantee as it is something that should have done? I have included below the “description of works to be carried out” given by the builder. If not, what sort of contractor do I need to ask to fix this?

Thanks all!

Link to additional photo:

Description Of Works To Be Carried Out:
• Remove all render and lead to flashing to party walls and chimney stacks.
• Repair any badly damaged uncoverd brick work.
• Install lead flashing to newly uncovered brick works to party walls of 25 meters, using 12inch code 4 lead with correct upstands for water tight measure at 150mm with 20mm internal into brickworks.
• Install render stop beads to meet lead flashings covering 75mm for water measures.
• Apply render scratch coat to all uncovered brick works to party walls using a 3-1 mix ratio of plastering sand and cement leaving to dry for 24hr.
• Apply render finish coat to newly applied scratch coat using a 3-1 mix ratio of plastering sand and cement.
• Remove badly installed valley tiles and valley liner.
• Install new zinc valley liner.
• Install new valley cut tiles correctly with a 100mm center valley for rain fall to run freely to guttering.
• Remove all loose ridge tiles and mortar.
• Rebed ridge tiles using a 3-1 mix ratio of building sand and cement.
• Remove all debris and waste from site.

.Description Of Works To Be Carried Out: Additional works
• Supply scaffold access tower
• Remove existing tiles/felt batons to back addition roof.
• Strengthen roof structure using 4/2 timbers fitted using 60mm screws.
• Install felt membrane to newly strengthened roof structure.
• Install 25/50 mm batons fitted using 50mm ring shank nails fired in using gas powed nail guns add correct for 49 tiles of at 300mm.
• Tile roof using existing tiles replacing any broken/damaged tiles.