6 Increases in rateable value after 1st April 1990
1 Subject to the following provisions of these Regulations, this regulation applies where—
(a) there is a notional rateable value determined for any lands and heritages for a prescribed financial year under regulation 4; and
(b) the rateable value of those lands and heritages which appeared in the valuation roll on 1st April 1990 is increased with effect from a date later than that date, except in the circumstances described in regulation 5(3)(a)(i).
2 In any case to which this regulation applies, the reference in regulation 3(1)(a) to “that notional rateable value” shall be construed, as from the date on which the increase in the rateable value of those lands and heritages takes effect, as referring to the sum of—
(a) the notional rateable value for those lands and heritages for the prescribed financial year in question; and
(b) the amount by which the rateable value of those lands and heritages appearing in the valuation roll on that date has been increased from the amount which appeared in that roll on 1st April 1990.