Just some thoughts - please consider the weight of the 3 or 4 bikes on the back of a Jazz, I have carried up to 3 bikes on Volvo and Subaru estates and they made the vehicles less stable.
I always put our bikes into the jazz the car can take 2 full sized easily with fr wheels off.
When I watched the Tour oF Britain last year all the team cars had the traditional roof carriers making bikes safe & out out of reach.