Regulation 3 Categories of premises – general
The category into which premises fall for the purposes of these Regulations is to be determined by reference to the position as at the date on which the fee in question is due.
In particular, the rateable value of premises for the purposes of these Regulations is to be that shown on the valuation roll in respect of the date in question.
Where a rateable value is changed with retrospective effect so as to place premises on a particular date in a different category from that by reference to which a fee due on that date has been paid, the appropriate amount is to be paid to the relevant Board or repaid by it (as the case may be).
In paragraph (3), “the appropriate amount” is the difference between–
the fee paid; and
the fee which would have been payable had the new rateable value been shown on the valuation roll as at the date on which the fee was due.