Wanted: child step for toilet etc

I'm looking for a child step to reach the toilet/sink in our bathroom, one around 30 cm high. Something like the IKEA Bolmen https://www.ikea.com/gb/en/p/bolmen-step-stool-white-60265163/ but not the shorter one that's 13cm, I need something taller but still reasonably compact.

If your child has grown out of needing this, I'd love to give it a new home.