The service would be about £300. No different from any other Lexus model. Did you shop around the dealers? Prices can vary between them.
I wouldn't have brought tyres from a dealer, they can be obtained cheaper elsewhere.
Our gold membership can get you up to 15% off dealer servicing.
I have the service history for my car, it's 20,000 mile service cost over £700 with new pads and discs etc. Just had it's 40,000 mile service and it cost me about £250 and the brakes are only 30% worn. So either the previous owner used to keep his foot on the brake all the time of the dealer changed things that really didn't need doing. They also charged him for 2 air filters!