Parking on a steep diagonal slope

Mr H

Next week, I will need to put my caravan on a slope that is both steep front to back and also side to side (i.e. a diagonal slope towards the back. I would estimate side to side is about 8" (200mm). My concern is that when the caravan is on the sloping plastic
block, it might turn sideways when loaded. Should I make a wider wooden alternative just for this case?