Transferring child tax credits to spouse

Hello, Past two years, I have claiming 0 child benefit as my income went over £50K. But my wife is stay at home mother and I would like to ensure that while we can't claim the benefit itself she can get the child tax credit (assuming that is the right thing to do). I would like to know - 1. How do I transfer the benefits over to her (still claiming £0) 2. Back date/transfer child tax credits for last two years so it shows in her NI records?

Hi,
Thank you for your query.
Your wife will need to complete form CF411A to apply for the child benefit National Insurance credits (not child tax credits) to be transferred from your National Insurance contributions records, to hers.
Please see the following link:
Apply for National Insurance credits if you’re a parent or carer 
Please refer to the notes for information on time limits of when to apply. 
Thank you.
 

Because my wife wasn't working I thought the NI credits has to be linked to my account. If my wife fills the form CF411A to apply for the child benefit National Insurance credits to be transferred from my National Insurance contributions records, to hers can they be done retrospective (from the time I started getting the NI credits) ?

Hi,

Yes, you can apply retrospectively on CF411A to transfer Class3 Child Benefit credits.

Thank you.