The crew of a UK ship is engaged on a standard Unlimited Trading Voyage Agreement. Under what conditions may a seaman give notice to terminate his agreement?

Any crew member who has served for at least 3 calendar months may give his notice not later than 7 days before the ship is due to arrive at any port in the country specified in the Notice Clause. 

However, his notice will not take effect: (a) if the ship is due to proceed to a port in the UK without leaving the Near Coastal Area; or (b) if the ship is due to reach a port in the UK within 7 days of leaving the Near Coastal Area.