Repair of undertile felt

[briwire]

I have a buyer for my late Mum's house and her survey came back with "the protective underfelt in the loft space is damaged/ripped and needs to be repaired before completion".
I have been up there today to investigate and seen that there are places where the felt edges have sagged, exposing the tiles above. I think this can be remedied by returning the felt to its original position and perhaps holding in place with battens.
I also noticed about half a dozen holes randomly positioned throughout the roof almost as if something had fallen through. They vary from finger size to fist size. The condition of the surrounding felt seems sound. It is approx 40 years old.
I've been looking for tips on youtube and seen this type of problem fixed using Bostik flashband.
I don't want to spend a great deal of money on this, just want to placate the surveyor/buyer.
Any thoughts or tips on this course of repair.

 

[^woody^]

Unless you can do a nice job with bitumen felt and blend it in and hope for a not too keen surveyor, there may be a chance. Otherwise it will look a right bodge and attract more attention than just leaving it and expect to reduce the asking price.

 

[Mottie]

We had a type of bitumen/paper felt on our 60’s house. If you touched it, it crumbled. After a big storm in the 90's a few tiles came off and the felt was destroyed. Insurance company for the whole roof to be stripped off, re-felted and battened and original tiles refitted.