It would be unusual for each of the owners to own their house but then for the lane to be owned by 4 residents. It might be worthwhile checking the title deeds to see actually is registered as the owner of the lane if it’s registered at the land Registry NI.
There is a legal doctrine of mutual benefit and burden. If someone has the benefit of using something, they have the burden of repairing it in proportion to the use. There may be another provision in the deeds for repair but in the absence of another provision, that is the situation.
If an adjoining landowner has land which has subsided and that subsidence is something that could have been avoided by maintenance or proper drainage or suchlike and that subsidence then affects adjoining property (the lane) then the owner of the lane has a claim in negligence against the owner of the subsiding land.
You mentioned the fear drop from the lane into the field and it may not be as straightforward as in the previous paragraph if there is some kind of banking which supports the lane in which case, it could be the lane owners who are responsible for this.
Whether blame could be laid at the feet of the adjoining landowner would depend on the reason for the subsidence.
Can I clarify anything for you?
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