Thanks for the post you have just reminded me to get a decent jack, have used our once and found that to lift the rear it was fully extended and just did not look safe, I expect I shall get a decent bottle jack .
Having had some experience of having to jack up vehicles, Ex AA patrolman of the 70 's when we did repair cars on the roadside, you would not get me using one of their jacks, or their tyre repair and inflation kit.
Either buy a jack that will take the weight or join one of the breakdown services. I know which I would use.
Bottle jack or trolley jack as a replacement? and what lifting capacity? The max weight of the vehicle is 4450kg fully loaded. My guess for lifting one rear wheel is that I need 2000kg lifting capacity minimum.