A pool noodle sounds like the only thing at present.

I would suggest a pool noodle also.

Can you get a thin price of foam cut to size? Clark rubber or something similar could help, or roll up a towel?

Can you cut a slit down the middle of a pool noodle and slide that over the railing?

Did your daughter used to roll over onto the wooden rails of her cot? You probably wouldn’t have heard the noise if she did. Unfortunately I don’t know how you can stop her that is a safe method.

If she isn’t rolling out can you take the side rails off. Sleeping on a mattress on the floor shouldn’t be a step back they just learn not to roll off without the risk of a big fall and then graduate to the bed. Same idea behind a toddler bed.

Try tucking her in tighter?

She’s not rolling off the bed its just she’s hitting the sides of it if she rolls over in her sleep, shes been in this bed for months and she sleeps right through. I don’t think putting a mattress on the floor is a solution as then she may take a step backwards and never know how to sleep properly in a bed. This is the bed she has

Can you add a secured lining ? Otherwise I would put the mattress on the floor as well.

When my eldest moved to her own bed, she rolled off regularly and hit her head on the walls too. I ended up just keeping her mattress on the floor and she learnt to stop hitting her head eventually.

I don’t know the bed type at all but would it be a safe option to pop a pool noodle over the rail?