As soon as practicable after a fortification removal order is withdrawn under section 20 , the Commissioner must –

(a) ensure that all reasonable efforts are made to serve a copy of the notice of withdrawal on the owner or, if there is more than one owner, on at least one owner, of the premises in respect of which the notice is given; and

(b) cause a copy of the notice of withdrawal to be affixed –

(i) to the entrance of the premises to which the order applied; or

(ii) in a conspicuous place near that entrance.