Marnie good idea with the hole cut out for the jack to go in.
I used the puck method before but it was sitting on top of what I thought was chunky wood. Anyway the wood cracked and unbeknown to me as I was jacking up the car the cracked wood was wedging up the sill at the same time.
£600 repair for carelessness
I promised myself I would get a large headed jack so the puck could sit inside so no need for wood.