Kids Merida problems

Eldest son has broken the plastic Bashrings on the crankset of his Merida matts JR24.
It had one mounted either side of the chainring and both through use have broken, can’t find a replacement and seems his chain has started derailing since these broke, any ideas??

Is he tall enough for some 165mm cranks and a N/W ring?

Or is he tall enough for 152mm cranks and a narrow wide?

Have you spoken to Merida?

Awesome customer service when I thought I should get some bearings for LRS before it was too late to do so.

And again before that back when they were mukshop and I snapped a chainstay on a carrera built by them.