Here is a very useful article by Bonallack and Sewell solicitors on missing freeholders.
Missing Freeholders and Lease Extensions | Specialist Solicitors | Bonallack & Bishop Solicitors
Vesting Orders – the solution to Absentee Freeholders – Specialist Solicitors Missing freeholders – the very real problems Having no contact with an absentee freeholder, and with no way to track them down, can be a major problem if you own a leasehold flat. Why?