386. Qualified duty to consent to assignment etc.

In any case where:

  1.  

    (1)     a tenancy1 includes a covenant2 on the part of the tenant3 not to enter into one or more of the following transactions (that is to say, assigning, underletting, charging or parting with the possession of, the premises comprised in the tenancy or any part of the premises) without the landlord's consent4 or without the consent of some other person5; but

  2.  

    (2)     the covenant is subject to the qualification that the consent is not to be unreasonably withheld (whether or not it is also subject to any other qualification)6,

then, where there is served on the