How have the courts interpreted the qualification clause in a commercial lease agreement?

Subsequently, in the case of Treloar v. Bigge (1874), L.R. 9 Exch. 151, the qualification appeared not as a deemed proviso but as an express part of the lease. The end result was the same. At pp. 154-55 the court said: Now the rule of law, no doubt, is that any words in a deed which impose an obligation upon another amount to a covenant by him; but the words must be so used as to shew an intention that there should be an agreement between covenantor and convenantee to do or not to do a particular thing. I cannot find any such intention here. The words, taken grammatically, do not seem to me to amount to an undertaking by the lessor, but are a part of the same sentence as that containing the lessee’s covenant, and qualify its generality. They prevent that covenant operating in any case of arbitrary refusal on the part of the lessor, that is, in any case where, without fair, solid, and substantial cause, and without reason given, the lessor refuses his assent.