Claiming Child Benefit after ILR - No NI number.

I would like to transfer the child benefit I am receiving to my wife who has recently been granted Indefinite Leave to remain. This way she can build up NI credits towards the state pension.

She has never worked and also does not have a National Insurance number.
I phoned the helpline but they were not sure on the procedure as I thought the child benefit office would automatically issue an NI number when she claims. There is a question on the claim form that asks if you have a NI number.

I was told she may have to attend a Jobcentre interview for a NI number but do they give numbers just for the purpose of claiming child benefit? I could not get an answer.
I thought you had to be planning to start work before they issues a NI number, which my wife is not planning to do yet.

Has anyone applied for child benefit without first having a National Insurance number?
Can anyone please share their experiences.