Upvote:2
Four months with no answer, hmmmm....
From comments...
What this means is that child visitor visa does not 'automatically' switch to a standard visitor just because the person turned 18. If you continue to use the visa (which is ok), you need to abide the terms and conditions, like accompanied by a parent or chaperone. Hopefully the carrier will prevent you from boarding if they see you are in breach.
If you want to travel on your own, you can apply for a standard visitor visa and explain that you are living an independent life and need a visa commensurate with your lifestyle.