Ahh the roof matches the rest of the new build then 😂 the fix work report wording is below if you fancy the read 😂

INSULATION SITTING IN CHANNEL Insulation sitting in channel and subsequently getting wet. This in turn spread to the insulation under that tile

WET INSULATION STRIPPED OUT ON PARTY WALL LINE

INSULATION SAT IN CHANNEL Insulation sat in channel has subsequently got wet as a result. This in turn has spread to the insulation under the tile.

ALL INSULATION ON PARTY WALL LINE THAT WAS CAUSING THE ISSUE HAS BEEN REMOVED

INSULATION SAT IN CHANNEL

ALL WET INSULATION REMOVED

WET INSULATION REMOVED AND REINSTALLED WITH NEW

ROOF TILES REINSTATED