7. Where the Commissioners vary any condition or restriction to which an approval is subject or revoke an approval(1), the Commissioners must give notice of the variation or revocation to the approved person which—
(a)states the date on which the variation or revocation has effect which cannot be earlier than the date the notice is given,
(b)in the case of a variation, identifies how the approval is varied, and
(c)gives the reasons for the variation or revocation.
Under section 49(4) of the Finance (No. 2) Act 2017 the Commissioners may at any time for reasonable cause vary the terms of, or revoke, an approval under that section.