6. Where an undertaking carried on by a Company in the financial year 1993-94 consists of or comprises lands and heritages in two or more rating areas which fall within the prescribed class of lands and heritages, the rateable value determined in accordance with article 5 shall be apportioned among the local authorities for the rating areas concerned in the proportion which the area of the prescribed lands and heritages in each rating area in that financial year bears to the total area of the prescribed lands and heritages of the undertaking in that financial year.