No this figure was for three years. It is the "Return to Invoice" protection, but only covers up to £10,000 difference between the invoice cost and what any payout would be. I don't know the car you are buying, but based upon trade in values after three years, I don't think you would need any more protection than this.
To be honest, the figure MINI quotes varies drastically. I think my quote for Gap insurance off MINI was nearly £600!
Well worth haggling, if they don't move, buy from elsewhere!