24” wheel dirt jumper?

[Slennons!]

My boy has outgrown his 18” BMX and would like a dirt jumper instead. 
His 24” wheeled Propain Yuma fits him perfectly but a 26” dirt jumper will be massive for him so I’d like to get him a 24” dirt jumper. 
My thinking is that the skills will be more transferable to his Yuma than a BMX. 
Problem is that 24” dirt jumpers don’t seem to exist in SA, even second hand
Does anyone have any suggestions please? 
Many thanks 🙏