Last year we chose to go by taxi from the 'new rank' at top right of the square in PP. It was 15 euros each way for 4 of us.
As previously mentioned there are very few buses that stop at CSV- we only found one about 10.30am and for return at about 4.30pm. When we phoned for return journey it was barely 10 minutes before the taxi arrived. Convenience was worth the cost!