6In this Part of this Schedule—
" the principal Act" means the [1967 c. 9.] General Rate Act 1967 ;
" owner ", in relation to a mooring, means any person for the time being receiving or entitled to receive the rack-rent of the mooring, whether on his own account or as agent or trustee for any other person, or who would so receive or be entitled to receive that rent if the mooring were let on a rack-rent,
and any other expression which is also used in the principal Act has the same meaning as in that Act.