we tried one of the one's that goes on the car with a tow bar, fine if you are not towing!!! At moment go for bikes in the van whilst towing but currently planning on changing car...x
Best way would be bike rack on back of caravan if it has mounting points, your dealer can advise on this & fit it as well. The extra weight on the back does not seem to bother 1000s of Dutch caravanners who use this method.
Or use a towbar mounted rack provided car has a high noseweight limit to take weight of of bikes & caravan, but obviously there must be sufficient clearance on turns. On UK built caravan, A frame is usualy to short for A frame rack.
We have tried all options including on back of van and can only recommend the roof option (i carry a small aluminium 2 step ladder) which is useful for bikes and awning.
We have them on a Fiamma rack on the rear of the caravan which works fine for us and we have traveled to Spain and back 3 times without any problem. We have a Swift made caravan though which have built in fixings so no problem. I don't believe that a Bailey caravan is suitable but I may be wrong.