Sch 15 para 42
If neither paragraph 40 nor paragraph 41 applies in relation to a post-activation period, the “ adjusted activated TTH amount ” for the purposes of paragraph 39 is— (a) an amount equal to the closing balance of activated TTH for the immediately preceding accounting period, if it is greater than nil, or (b) nil, if the closing balance of activated TTH for the immediately preceding accounting period is nil or a negative amount.