This section applies if a mortgagee of land which consists, or substantially consists, of a dwelling-house brings an action for the enforcement of his security, and at the relevant time there is—
in the case of unregistered land, a land charge of Class F registered against the person who is the estate owner at the relevant time or any person who, where the estate owner is a trustee, preceded him as trustee during the subsistence of the mortgage; or
in the case of registered land, a subsisting registration of—
a notice under section 31(10);
a notice under section 2(8) of the Matrimonial Homes Act 1983; or
a notice or caution under section 2(7) of the Matrimonial Homes Act 1967.
If the person on whose behalf—
the land charge is registered, or
the notice or caution is entered,
is not a party to the action, the mortgagee must serve notice of the action on him.
If—
an official search has been made on behalf of the mortgagee which would disclose any land charge of Class F, notice or caution within subsection (1)(a) or (b),
a certificate of the result of the search has been issued, and
the action is commenced within the priority period,
the relevant time is the date of the certificate.
In any other case the relevant time is the time when the action is commenced.
The priority period is, for both registered and unregistered land, the period for which, in accordance with section 11(5) and (6) of the Land Charges Act 1972, a certificate on an official search operates in favour of a purchaser.