Jacking up the caravan

 if you don't feel confident in jacking your caravan & have AA/Mayday/etc, them them do it. I put the jack under an axle when I lift mine, but I use a big trolly jack at home. Attaching it to the car when jack is good, but not always possible.

I fitted a similar thing to our van called a Kojack I have only used it on the drive when I  have removed the wheels one at time to have new tyres fitted and making sure the corner steadies are raised on the opposite side 

I have used the same item in the past and apart from a jack, which kept leaking, the brackets were good and provided a safe place for the head of the bottle jack. I would recommend trying to find a piece of steel or aluminium plate about 5mm thick and about 200mm square to place under the bottle jack when the jacking surface is soft or uneven. I have had a jack slip before when it started to sink into the ground. No damage, but not recommended.