MG MG4 Owner's Handbook Manual page 124

SEATS AND RESTRAINTS
As children grow and become older/larger, it will get to
the stage when they no longer require child seat restraints.
At this point they will require use of the vehicle standard
seatbelt. Please ensure the seat belt is correctly positioned
on the body of the child.
When fastening a seat belt for a child, always check it
for correct positioning. Adjust the height of seat belt to
ensure the shoulder belt is kept away from the child's face
and neck. Position the lap belt across the hips as low
as possible, and tighten adequately. Correct positioning
means that the seat belts can pass the applied force to the
strongest part of the child's body in accidents.
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If the shoulder belt is too close to the child's face or neck,
it may be necessary to use a child booster cushion (always
ensure that it meets any relevant laws or standards).