Two bikes in my van. I just use a couple of bungees and a lock, one bungee on the rear wheel and one bungee going from floor to ceiling, between the frame and cranks. Living in Milton Keynes, the round about centre of the world, I can state this works well. (I drive about 500 miles per week like this, medium size Ful Sus 29er and a road bike go in no bother, no need to remove wheels.
I then use a 100cm Krptonite NY Forget About It lock, this is more for added security rather than anything else, I tend to travel with the bikes in the back on overnight jaunts. The lock goes between the chainstays/wheel through to a secure metal frame behind the cab.
Zero movement of gear. The van is a Citroen Berlingo, it has the O rings on the floor with hooks/holes in the roof area for the bungees to secure on to. Leaves me with loads of room to use the van as a changing room when I need to.