Kids or small MTB advice

[Bit of a Unit]

Hi there,

Any suggestions appreciated.

11 year old lad, 140 cm tall, and 65 cm inside leg. Just started using the excellent mountain biking facilities at the national cycling centre after a few years on the bmx track.

I'd like to get him a decent mountain bike budget around £400 as the kids bikes he has had so far he destroys quickly due to the fearless nature of his cycling!

Not sure if he has a couple of years left on a kids bike or a small adult mountain bike

Thanks

[SpamDisco]

Last year bought our 11 year old a dirt mountain bike, as they have full size wheels but a smaller frame. He took to it well and doesn't look like a child's bike
Can't really recommend a brand as he's not really an enthusiast.