(1)Subject to the provisions of this section and section 168, where the Board have—
(a)determined to issue, cancel or vary a contracting-out certificate or an appropriate scheme certificate; or
(b)determined to make, or not to make, any order which they have power to make under section 132, 135 or 138; or
(c)determined any other question which it is within their functions to determine,
their determination shall be final.
(2)The Board may on the application of a person appearing to them to be interested—
(a)at any time review any such determination of theirs as is mentioned in subsection (1), or a determination given by them on a previous review, if they are satisfied that there has been a relevant change of circumstances since the determination was made, or that the determination was made in ignorance of a material fact or based on a mistake as to a material fact or was erroneous in point of law;
(b)at any time within a period of six months from the date of the determination, or within such longer period as they may allow in any particular case, review such a determination on any ground.
(3)The Board’s powers on a review under this section shall include power—
(a)to vary or revoke any determination or order previously made;
(b)to substitute a different determination or order; and
(c)generally to deal with the matters arising on the review as if they had arisen on the original determination.