The valuation formulae are complex but are primarily based on compensation for loss of ground rent and the length of the unexpired term.
Browsing: Extending Your Lease
The Law Society of England and Wales is advising leasehold property owners to take advantage of lower property values and extend their leases.
One way of obtaining a long lease is to collaborate with other owners in the building to exercise the right to collective enfranchisement.
Selling with a short lease can be overcome and this can increase the value and the marketability of a flat.