I paid for the 5 years service package at £500.00 and , as I paid it 6 months ago, I have forgotten it; until I had my first service in early August, which was free of all charges, and the dealer even offered me a courtesy car.
I think the £145 sounds about right. The next service will be around £165, I think. 3 years paid servicing works out roughly to the 5 years package price, and the balance on the package can be passed on (better trade-in value if you decide to p/x early).