Our nearly 1year old puppy LabX has always travelled in the back boot of an estate car with a dog guard up. She’s very calm and thinking ahead to summer camping hols, longer car journeys we would like to try her on the back seat between the kids in a car seat belt harness. Knowing her she would just falls asleep with her head on a kids lap as she’s such a soppy dog. Any thing we should look for in buying a good car seat harness for a medium size strong breed? I’ve googled and like most things prices vary a lot, so I’m not sure what to look for. We walk her using a mekuti harness which she’s fine wearing.