Boundary Disputes: Trying to locate a Boundary Dispute Expert?

Boundary Disputes: Trying to locate a Boundary Dispute Expert? If someone has a boundary dispute, for example a piece of ground that the next door neighbour has erected a fence on, other than a solicitor or Chartered Surveyor, who could once consult? Are there specific Boundary dispute experts that know all the land registry ins and outs and have a more detailed knowledge than a typical solicitor or chartered surveryor? Thanks. Fraser