Get the JD Bug Original Street (£50) over the Junior Street (£30). The folding mechanism is far better and stronger. I’ve sold hundreds at work and never had a problem with one unless an older/bigger sibling or parent has been on it and broke it. Even if that has happened, it’s been few and far between.
If you want to treat the kid, MGP VX6 Pro (£100).
Roughly I usually see 6 to 8yr olds getting a JD Bug, 8 to 12yr olds getting the MGP Pro, then 12+ getting an MGP Team (£150).
Both scooters will last years, eventually as the kid gets bigger and more reckless the bearings will need swapping out in the wheels, but by them the wheels are usually shot, so spend £10/£15 and replace the lot.