chimney stack insurance question

We are thinking of making an offer on a property whose chimney stack is leaning and the chimney brickwork has deteriorated. The property is a 30s S/D and the chimney stack stands in the middle between the two properties, so it’s a shared responsibility between the two neighbours. We’ve talked to the next-door neighbour who said that she’d had it investigated by her insurance company and was told it is wear and tear and needs to be repaired. We don’t mind paying to get it rebuilt/repaired but we are concerned we won’t be able to insure against the risk of it falling and causing damage to persons and/or property as the lean is a pre-existing condition. Our solicitor has advised us to make it a condition of the offer that the seller repairs the stack before completion but it is an executor sale and we are worried they are just going pass us by and accept the offer of a less ‘fussy’ bidder. We like the property a lot – is there any insurance policy we could take out to cover ourselves against the risk of the chimney falling down before remedial works have been completed?