Subject to subsection (2), any limit for the time being determined by or for a local authority under section 3, or applicable to it under section 4 or 12A, shall be treated for the purposes of this Chapter as increased by the amount of any payment which—
is due to the authority in the period to which the limit relates, but
has not yet been received by it.
In the case of a limit determined under section 3, or set under section 4(2) or 12A, subsection (1) shall not apply to any payment whose delayed receipt was taken into account in arriving at the limit.