Six hours on the road with a three-year-old is not planned like a business return trip. Seats, breaks, timing: here is what actually works.
Baby seats and boosters are provided at no extra charge, provided you ask when booking: they are not in the boot by default. Give each child's age and weight, as that determines which approved model is fitted.
On a journey over four hours, a break every two hours is the rule, and it matters as much for the child as for the driver. We favour service areas with a playground and water point over roadside filling stations.
A night departure is worth considering with young children: they sleep for most of the drive, the road is clear and you arrive in the early morning. It is often the most restful option for everyone.