Its no use picking away at the plaster and constantly posting about the situation - leave it alone until a professional arrives.
You will have difficulty getting an inspection ladder up between the dormers, although a ladder could be raise to the left of your dormer, and the roofer(?) could walk up and down the valleys.
Probably, a bit of bridging scaffold, or a wide straddling tower, would provide work access.
Forget price guesswork - how can even a ballpark figure be given when you dont know what you are pricing for?
If the whole house slate roof does need replacing, then go for that with the remedial works bolted on.
You might be offered a re-roof price, and a day rate for the remedial repairs.
Perhaps post your quotes on here for discussion.
Stay with your valuable natural slate, dont be talked into any kind of tile.
Removed carefully, 95% of in-situ slate can be re-used.
You will have difficulty getting an inspection ladder up between the dormers, although a ladder could be raise to the left of your dormer, and the roofer(?) could walk up and down the valleys.
Probably, a bit of bridging scaffold, or a wide straddling tower, would provide work access.
Forget price guesswork - how can even a ballpark figure be given when you dont know what you are pricing for?
If the whole house slate roof does need replacing, then go for that with the remedial works bolted on.
You might be offered a re-roof price, and a day rate for the remedial repairs.
Perhaps post your quotes on here for discussion.
Stay with your valuable natural slate, dont be talked into any kind of tile.
Removed carefully, 95% of in-situ slate can be re-used.