In this Part—
means a person (other than a mortgagee not in possession) who is for the time being entitled to dispose of the fee simple in the premises, whether in possession or reversion, and
includes also a person holding or entitled to the rents and profits of the premises under a lease of which the unexpired term exceeds three years.
"disposal", in relation to land, includes a conveyance of, or contract to convey, an estate or interest not previously in existence;
"owner", in relation to premises—