Property owners are often neglectful of their boundaries until it is to late. Once the neighbour has chopped down that tree that you thought was yours it is extremely hard to put it back up again.
However if you have suitable tile deeds then it is possible to attempt to resolve many disputes. Measurements can be taken and pegs knocked in to enable a boundary line to be established. Alternatively documents photographs and drawings can be prepared to support (or disprove) a county court action for compensation and or to get a hedge or fence re-erected in its correct location.
Unfortunately the help we can give is only as good as your title deeds. The current land registry title plans are not very accurate and only enable boundaries to be measured to the nearest half a it is wise to agree the ownership of any unclear boundaries with your prospective neighbours.metre. This is due to the small scale of the plans on which the boundaries of a property are drawn. It is thus well worth saving copies of old tile deeds with measurements or drawings, if you have them.