Where can my kid try out a new bike?

Looking for recommendations for a kids 24" mountain or hybrid bike for about £300?

So far we have been able to try our bikes at Smyth's (Fort) and Decathlon.

Evans Cycles seem to have zero in store stock and Dales and Tiso are beyond our budget. We have tried 2 Halfords, one had very little space in the aisles to move on the bike and the other store flat out didn't allow it.

My kid prefers twist gears as opposed to triggers (I think this is more intuitive) and I would like the bike to be on the lighter side. I really like the bikes in Decathlon (although they had trigger gear shifter) but they were around 15kg.

Any help on models of bikes and where we might be able to try them is much appreciated.