620. Information held by superior landlord.

Until a day to be appointed1, if a request for a summary of relevant costs2 relates in whole or in part to relevant costs incurred by or on behalf of a superior landlord3, and the landlord to whom the request is made is not in possession of the relevant information4:


    (1)     he must in turn make a written request for the relevant information to the person who is his landlord (and so on, if that person is not himself the superior landlord)5;


    (2)     the superior landlord must comply with that request within a reasonable time6; and


    (3)     the immediate