6.—(1) For a circular service the appropriate sum is the amount in pounds sterling which is the greater of the sums specified in paragraphs 6(2) and 6(3).
(2) The sum specified in this paragraph is the lesser of—
(a)the sum calculated in accordance with the formula set out in paragraph 4; and
(b)the sum calculated in accordance with the formula set out in paragraph 7.
(3) The sum specified in this paragraph is the sum in pounds sterling equal to a quarter of the sum calculated in accordance with the formula set out in paragraph 4.