Hi Glenn
You don't state where you live, but as other posters herein have stated, email a few of your local dealers and do quote comparisons. There can be significant variations. I have the same vehicle as yourself on a 56-plate, but a manual, but has only covered 14k miles. I did exactly the same email trawl and have recently taken out a 3-year service plan with Lexus Sidcup (Ask for Samantha Artlett, 01322 611106 - mention my name and maybe I'll get a referrer's fee !) to cover the 40k, 50k and 60k services for £1094.76 (the dealer knocked off £191.07 to gain my business). Payments are being made over 20 months on interest free credit (are there any three sweeter words in the language, other, of course, than those you always want to hear from your girlfriend - "I'm not pregnant").
I've not had the first service yet, but it's imminent. Oh, the price also includes free MOTs for the duration of the service plan, free puncture repair and 10% discount on additional work.
Let us know how you get on, and I shall do likewise with my experience with Lexus Sidcup.