Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
Many people have failed to either drop their claim for child benefit or failed to register for self-assessment because of the child benefit tax charge so you aren't alone.
HMRC will probably catch up with you eventually but I'd suggest you call the tax office on the number here and explain the situation and they will either get you registered for self-assessment or direct you here so that you can register yourself.
I hope this helps but let me know if you have any further questions.
I have to go out for a while but will be back this afternoon to answer any follow up questions that you may have.
Hi again.I'm just following up to find out if my answer helped or if you have any further questions.