Thank you for your question
My name is ***** ***** I shall do my best to help you.
Make sure that you have a letter from the mother confirming her agreement to your permanently removing the children to the UK.
Nothing else is required.
Please ask if you need further details
Yes you shoudl bring their birth certificates with you.
When you settle in the Uk you will need to find a Primary School with space to take them on.
The letter should be witnessed but nothing more complex
I shall ask Customer services to deal with this for you
Which part are you uncertain of?
Your children are British Citizens and are entitled to enter the Uk with their parent - you.
The only reason that you need the letter is so that in the event that your wife regrets agreeing to the arrangement and trie sto claim that you abducted the children you have the evidence that this is not true.
There is no specific wording - it simply needs to make clear that she knew they were moving permanently to the UK