4B.—(1) Where a hereditament to whichF1 paragraph 4 or paragraph 4A applies is distinguished in the valuation list as being occupied and used partly forF1 industrial purposes or transport purposes and partly for other purposes, its rateable value shall be the aggregate of—
[F2F1(za)the relevant percentage (if any) specified in paragraph 4(3) of so much of its net annual value as is shown in the list as apportioned to the occupation and use of the hereditament for industrial purposes;]
(a)one quarter of so much of its net annual value as is shown in the list as apportioned to the occupation and use of the hereditament for transport purposes, if any; and
(b)the whole of so much of its net annual value as is shown in the list as apportioned to the occupation and use of the hereditament for purposes other thanF1 industrial purposes or transport purposes.
(2) For the purposes of this paragraph the property of the Belfast Harbour Commissioners within the limits of the port and harbour of Belfast, as defined by the Belfast Harbour Act 1882, held by the said Commissioners and in their actual occupation for their own use or for public purposes, shall be deemed to be a freight-transport hereditament occupied and used wholly for transport purposes.