21.—(1) An inspector may serve a notice on any person who contravenes, or who the inspector has reasonable grounds to suspect may contravene, these Regulations—
(a)requiring that person to act in accordance with the Regulations (an “enforcement notice”);
(b)prohibiting that person from acting in breach of them (a “prohibition notice”).
(2) The notice must give reasons for serving it and, if appropriate, specify what action must be taken and give time limits.