In reply to VPJB:
Dancing Ledges at Swanage, the lower ledge.
Ideal for children on a calm day* and easy to set up bottom ropes. I introduced my kids to the sport there.
* beware however if it's rough and the sea is breaking over the ledge as sadly there have been drownings here, but only in a high running sea.
I know it's not Wales. but you did also say Europe!