While the Touran has seven seats it is a more compact vehicle, so the easiest option would be to tilt or slide the second row to allow easier access to the third row for the child seats. However, a larger vehicle would make it easier for all passengers and allow an adult to sit between the two child seats so the younger children can be attended to if necessary. We would suggest looking at vehicles such as the Volkswagen Multivan, Volkswagen Sharan or SEAT Alhambra, as these have sliding side doors to give better access and flexible interior seating, so you can have the child seats in the second row while allowing access to the third row for the third adult.