I'm in the process of trying to get quotes for a leak which I believe is around the dormer window. Water comes inside the bedroom and also in the roof of an integral garage. Only one tradesman has replied so far, but as far as I can tell they did not go up onto the roof to assess the problem. It is possible to determine where a leak is without examining a roof or seeing where the water leaks inside? They have said that the shiplap needs replacing on one side (it's currently boarded up but only to see if it was the cause of the leak - it wasn't) and all of the flashing around the dormer. Is it normal to replace all of the flashing, if only one side of it is thought to be the cause of the issue? I have looked at the roof myself (I am no roofer) and was unable to see any obvious problems with the flashing or any tiles. The shiplap was boarded over at that time. The quote is for 860 (not sure if VAT included) and I have no idea if this is a fair price or even if I should trust them to go ahead.