Junior has his new pedals and shoes.
I’ve fitted the cleats (20 degree float initially) – I’ve done many Shimano road and mtb cleats before, so sort of know what I’m doing.
He’s managing to clip in OK, but only able to unclip by pulling his heel in rather than out – which would be my natural way of doing it. He’s really trying, but they won’t unlip going that way.
What have I done/setup wrong?

mallet DH or Mallet Enduro?

I have a set of mallet endures which, combined with my size 12 feet were a pain in the ass to get out of until I swapped to the longer axle kit. My toes would hit the crank arm before the pedal released.

Also have a look at the grub screws. Push them all the way in and see if it works ok. It might be an area of the shoe sole catches the grub shoe which stops him twisting his foot. Had this with a pair of specialized 2fo and the mallet DH.

Failing that then the shoe sole round the cleat recess may be stopping the release.

Toe of the shoe or part of the sole being stopped by the crank arm or catching on the pins stopping the shoe from twisting out?

Thanks Gotama – It’s the DH Mallets – I’ll try your suggestions.
K – not sure, need to look a bit more closely.

Clip them in by hand and you should be able to see where’s fouling

Have you got the cleats on the right way?
One has a dot on, you fit this to either the left or the right depending what angle you want to uncleat

Thanks all. I swapped the cleats over to the 15 degree float position and he’s able to unclip heel out.
I’m not convinced there isn’t something else going on as amount of float shouldn’t dictate which way you unclip, but hey ho.