18. Secured creditor: value of security
(1) A secured creditor may, with the permission of the Court or (except where sub-paragraph (2) applies) the agreement of the Office-holder, at any time alter the value which that creditor has put upon a security in a proof.
(2) If a secured creditor —
(a) is the applicant for an administration order or is the person who has appointed the administrator and has in the application or the notice of appointment put a value on a security; or
(b) has voted in an administration or winding-up by the Court in relation to the unsecured balance of the secured creditor's debt,
the secured creditor may alter the value of a security only with the permission of the Court.