The illustrations reminded me of a kids book I picked up from the charity shop, not so long ago. Its from 1968 and it was illustrated by Ferelith Eccles Williams. The story is hilarious and of its time. Basically dads in a transit van and he keeps picking up people like Auntie Pat with baby Paul and they all go to the seaside in the back of the van. No seat belts or car seats then! They all have a bit of food that they bring with them and dad brings a bottle of beer and a newspaper! Cool illustrations though!
Images from Leila Berg 'A Day Out' and http://www.facebook.com/#!/plocmagazine