31.—(1) If any question arises whether the withholding of a consent was unreasonable it is for the landlord to show that it was not; and in determining that question the following matters, if shown by the landlord, are among those to be taken into account, namely—
(a)that the consent would lead to overcrowding of the dwelling-house; and
(b)that the landlord proposes to carry out works on the dwelling-house or on the building of which it forms part and that the proposed works will affect the accommodation likely to be used by the sub-tenant who would reside in the dwelling-house as a result of the consent.
(2) A consent may be validly given notwithstanding that it follows, rather than precedes, the action requiring it.
(3) A consent cannot be given subject to a condition, and if purporting to be given subject to a condition shall be treated as given unconditionally.
(4) Where the tenant has applied for a consent then—
(a)if the landlord refuses to give the consent it shall give to the tenant a written statement of the reasons why the consent was refused; and
(b)if the landlord neither gives nor refuses to give the consent within a reasonable time the consent shall be taken to have been withheld.
(5) In this Article a “consent” means a consent which is required by virtue of Article 30.