The Natural Philosopher wrote:

£2800 seems very low to me. Active rot in the roof as far as I am
concerned means its leaking, and possibly poorly ventilated as well,
which means a complete re-roof is probably what you want to do.

The damp behind the chimney is curious..perhaps water coming down
it..but if near the ground, perhaps the chimney is sucking it up.

Rotten window frames and a leaking bathroom are less an issue. You need
to rip the bathroom out and re-do it properly thats all, and you
probably would anyway.

Gee, you're not the bloke that put in the quote are you? ;-)