leaf 24 extended warranty

Hi all I have a 14 plate leaf 24. Does anyone know when I need to consider extend the warranty, and how I go about this? I recall something when I purchased it about a continuous 5 year period being needed?

Got a letter yesterday from Nissan offering me a year's extended warranty on my September 2014 Leaf 24, at just £44.90 per month (for 10 months). I take it no one is mad enough to take them up on it? When the monthly PCP is just £123, it represents a ridiculously high price!