I’m a high mileage user compared to most. My Kuga went back just over 5 years old and 106k miles on the clock.
Never had a single issue with motability paying for anything. I never contacted motability in fact.
Whenever I wanted a service or had an issue I rang a Ford dealer and they took the car in. I picked which Ford dealer on a whim depending on what suited me and never had issues with any.
Motability paid for pretty much anything the dealer said without issue. Even paid for the dealer to change my tyres instead of kwik fit and they where still legal.
You cant blame motability for manufacturers making a longlife service interval. The lease covers manufacturer servicing so it meets that. If you want more services then you cant expect them to pay.
If you consider your car has an issue thats a different matter , if the dealer won’t sort it go elsewhere or complain to motability.