(ShareCast News) - Oil and gas investment company Cluff Natural Resources said it is to concentrate on the farm-out of its advanced licences and that it will reapply for its 50% owned licences in the Southern North Sea.The AIM-listed company is to prioritise the advancement of and farm-out of its two most advanced licences, the P2248 licence, which recently found P50 prospective resources of 1.73trn cubic feet, and the P2252 licence.In October, the company received an extension on its 100% P2248 and P2252 licences for a further year to 30 November 2017 and that an extension had been applied on its 50% P2253 and P2258 licences by Burgate E&P, the licences' operator.However, Burgate was informed that the Oil & Gas Authority will not grant an extension of the initial term of the 50% P2253 and P2258 licences, which means the licences will expire on 30 November.The Oil & Gas Authority indicated that it expects to make the licences available in the next licencing round planned for the first half of 2017 where the company will re-apply for the licences under the Oil & Gas Authority's new terms.Chairman and chief executive Algy Cluff said: "These two 50% held licences represent the least mature assets in our oil and gas licence portfolio and a small proportion of our overall resource base."Our primary goal remains to pursue and secure the farm-out of our two most developed 100% held licences, P2248 and P2252, both of which we consider to be highly prospective and have the potential to transform our company."Shares in Cluff Natural Resources were down 1.28% to 4.61p at 1328 BST.