To be sure, you need to clarify a few unknowns, i read your screen shot, so the roof is fine, the felt is fine but there could be localised water damage?
That would probably mean removing some tiles and replacing some rotten wood etc, not particularly costly
If you re set on the house, then get a damp report but before you get one, make sure the home owner will allow full access, a damp report can be had for less than £150, your surveyor should know one.
Then get a competent roofer to look at what is required and costs, again, he needs full access.
Many older houses have some degree of "white" cement asbestos, its not a huge deal.
Then armed with your reports, go back to the seller with your 95k offer, if he wants top dollar he is going to have to fix the house up himself and he only has 25k to play with.