The servicing for my car is every year and like Michael said the dealer should contact you, Motability won’t, but on my first year the dealer never rang and I happened to be passing the dealer the day before the 365 days were up and the dealer did the service there and then so I saved them a few quid for my troubles.
This year being year number 2 and second service they did ring and booked it in.
So the bottom line is you need to keep an eye on the date the car needs to be service because you can’t rely on the dealer even though they get penalties from Motability of hard cash if they don’t service a car on time.