The sea survival course is one of the RYA's specialist one-day courses. In order to teach it you must qualify as an RYA sea survival instructor.
The instuctor course lasts four days and is organised centrally by the RYA. It is always heavily subscribed, so if you are interested in attending, please send your CV to the 'email RYA training' link above.
Prior to the course you must be an RYA cruising instructor (or higher) or advanced powerboat instructor and hold the sea survival course certificate yourself.