How to prevent a child to change lock screen?

[iMore Question]

Created a picture with a pone number, so if someone find the iPad mini, they can call us. But one of my kids love roblox a lot and like to alter the lock screen. How do i prevent this?
Enabled restrictions, but I cannot find something that disable change of lock screen there. Tried to Google, but no luck so far.
iPad mini, iOS 10.3.3

 

[Just_Me_D]

Can you not just tell your child to not change the lock screen?

 

[Annie_M]

Change your passcode and don’t tell your child what it is!

 

[nikkisharif]

Can you not just tell your child to not change the lock screen?

My thoughts exactly!! And if they don’t listen, then they don’t use it*