To put offer in house with a large stain on ceiling of lounge

[Kittley]

We've viewed a house that we like however there's a large stain on the ceiling of lounge (the bathroom is above it). Property has been rented out for 2 years and estate agent did bring up the stain before we spotted it saying the owner will get it checked to find out what's caused it (potentially leak from bath as house is 2 yrs old) and get it fixed before exchanging contract. Can anyone advise please how we go about this when we make an offer? Appreciate that even if we say our offer is subject to the potential leak being fixed, the owner can just paint it over and pretend it's been fixed. Do we say our offer is subject to ceiling issue being looked into and fixed with receipts to confirm before exchange? Ahhh thanks

You can make your offer conditional on it being addressed, yes. Your surveyor will be able to pick up whether it’s a live issue / ongoing leak which needs rectifying, or whether it’s just old cosmetic water damage which needs sealing and repainting.

What I find bizarre is that the seller doesn't seem to have put any effort into finding out what has caused it. It may have been tenanted but, if it has been repaired, the landlord or estate agent would know that. If it hasn't been, then it must be continuing.
My concern is that you know about this because there's a great big stain. What else is there which isn't so obvious?

Either you ask for it to be sorted, but this is fraught with difficulty. Probably easier to reduce your offer accordingly to allow enough to investigate and sort it out.