5. Where an undertaking carried on by a Company in the financial year 2000 01 or any of the four following financial years consists of or comprises lands and heritages in two or more local authority areas which fall within the prescribed class of lands and heritages, the rateable value determined in accordance with article 4 shall be apportioned among the local authorities concerned in the proportion which the area of the prescribed lands and heritages in each local authority area in that financial year bears to the total area of the lands and heritages concerned in that financial year.