When I bought mine I enquired about the service intervals and the dealer said
ALL UK Leons were factory set to 12 month/10000 miles and were changed at the
dealership if the customers usage indicated a higher mileage interval would be better.
When I bought the Service Plan they asked my annual mileage and the price came back from Seat taking it into account. No free plan when I bought but at under £11 a month for 34 payments it should save me over £113 compared to the prices on the showroom menu and website. Its also fixed thus I am protected against any price rises that are inevitable over 3 years.
Just make sure you get the Seat plan through VW finance. Dealer schemes are not a bargain because you cannot use another dealer if the seller cocks up plus you loose your money if the dealer goes bang. With the Seat scheme you can get the car serviced at any Seat dealer.