I’d look at the eSenstials servicing options from Hyundai themselves. Unless you have a particularly good independent garage that you know and trust it’s one of the better options. Even the base service gives you 12 months breakdown cover, and their MOT at £40 is a pretty good price.
As for warranty. A friend of mine is in the used car trade, he sells a lot of premium brand ex lease cars that he purchases from the finance companies. He recommends Warranty Wise.