New Bike For Teen

Hi, Looking to get a new MTB for my lad.

We have been to 3 local shops & 2 have said he is a 'Large' Hes about 5'9 at 13 (The other shop didn't have any in our price range)

Looking to Spend approx £500

So far we have looked at a Cube Aim Pro & Trek Marlin 4/5 (dependent on discount)

Are these good bike to look at or is there anything else that should be on the radar?

We would like to go to Cannock (nothing too mental)

Cheers for any advice

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