31.Sections 20 to 26 and 28 of the Act make further provision about the content and duration of notices and the procedure for making them, outline the appeals procedure and provide that failure by a landlord to comply with a notice will be an offence attracting a fine not exceeding level 5 on the standard scale. They also make provision for variation of notices, though not so as to shorten their duration. A local authority may revoke a notice at any time.