How to recover my daughter's iCloud account?

Dear All,

My daughters iCloud account is "Locked for security reasons".

I am unable to recover it because of the following...

[1] Forgotten password

[2] Forgotten security questions

[3] Recovery email address no longer active

So as you see, of the options Apple/iCloud give for recovery, I have access to none of them.

I have changed my AppleID (email address) on my account, but this is not reflected on my daughter's account which continues to send recovery information to my old now-defunct email address.

Can anyone advise if there is another way to regain access to her account (for family sharing). I don't want to have to create a new AppleID if it's not absolutely necessary.

Thanks in advance for any help/advice.

Kevin