Where a [F1 district council], being required under section 3 to issue a site licence in respect of any land, fail to do so within the period within which they are required to issue a site licence by that section, an offence is not committed under section 1 in respect of the land by the person by whom the application for the site licence was made at any time after the expiration of the said period and before a site licence is issued in pursuance of the said application.