Self Assessment Registration for a child

I have not been able to find an answer to this online and have just been cut off after being on hold to HMRC for 75 minutes, My daughter needs to pay CGT from a sale of shares and I cannot find how to Register for a Self Assessment for a child. I have just tried Registering for a Self Assessment online, but it will not allow me as the applicant is under 15 years and 9 months. Please can someone advise?

Hi SelfAssChild,

You can complete the fill in, print and post form:

Register for Self Assessment

Thank you.