Single wooden bed from John Lewis, needs repair (Peachcroft OX14)

This bed endured some jumping on over the years and eventually the slats started falling out. This was probably also due to the long planks on the frame bending slightly. The bed has been slept on recently, but it was a young, rather light, guest and we tried to secure the slats in position using blue tightening ropes that can be seen on the picture. A more secure solution is needed.
We will disassemble the bed for transport, if needed.