Central London CC, 3 September 2004. Defendant tenant (C) had a sub-underlease on a live/work unit in a building, the freehold of which was held by claimant landlord (BF). The existing headlease permitted the use of defined parts including C's unit as live/work units but the underlease remained unamended in the form of the original headlease stating that the building could not be used for any other purpose than as a factory and/or offices without written consent. C used his unit principally as living space with only a small work space. C gave notice under the Leasehold Reform and Urban Development Act 1993 s42 to claim a new extended lease. BF would not admit C's claim because the sub-underlease was a business tenancy for the purposes of s5(2) of the 1993 Act and the unit did not qualify as a separate flat. BF further contended that C was in breach of the user covenants and the Act did not confer rights on persons qualifying only on their own breaches of covenants. C countered that BF could not challenge his claim by relying on grounds not in BF's counternotice. "Held": claim dismissed. C was entitled to a new extended lease. BF was not entitled to depart from the issues detailed in its s45 counternotice and C's arguments were within the issues contained in the counternotice. The user clause in C's sub-underlease permitted either residential or working use or the two together. The definition of a separate flat in s101 was satisfied. The user covenant did not require the defendant to use the unit as a business premises.