just sayin but
you fascia an sofitt could be rottin - thers signs of a previous repair - because water from the roof is missin the gutter an gettin down the back an soakin the render below.
the felt an tiles should project over the gutter by about 40mm or so.
the lead bridgin soaker at the angle should be another 50mm forward.
thers holes bored in the fascia - for ventilation?
the first course of tile dont seem to have bird combs fitted?
Thanks, bobasd. My daughter's place. Little or no external maintenance in at the very least, 5 years. The roof tiles seem in good nick, but felting is very old and in a poor state. Think you are right about soffits and gutters. Will get a roofer to install the vent, and maybe give the place a once to see what is about to fail first!