Somewhat careless servicing which begs the question what else did they miss ?

Unless the car feels right to drive or you experience a fault before/during/after a test drive then walkaway from that particular car. Much depends on how much you are paying for a car but in general any car being sold by a garage/dealer must be in MOT condition otherwise it's not fit to sell/buy or drive.

I test drove several used cars prior to purchasing, 3 had problems, one (a diesel) was leaking exhaust fumes into the cabin, another a sudden lose of power and black smoke came from the exhaust (a petrol) I needed to gently limp it back to the garage, on 2 other cars the clutch biting point was too high which suggested the clutch has been ridded, walked away from them all. Suggest you do likewise if you find similar problems.