I have just expereinced a similar problem.
We placed an offer on a property subject to structual pests etc etc.
Inspection found sagging ceilings in the lounge and hall.
The report stated the sagging ceilings were not a structual fault.
We questioned the report with building inspector and he checked with the relevant dept.
Found to be not a strucual fault because ceiling still serving its purpose – ie ceiling has to be falling down before it’s a structual fault. The owner is not obliged to fix due to no structual fault.
So try your luck and negotiate with owners on cost of repair.
We had it fixed after settlement.

We still cant believe a ceiling almost falling on your head is deemed not a structual fault – CRAZY