VAT registration errors - Invalid VAT/GST registration number

Hi All, Can anyone please help. We are UK limited company and are VAT registred in UK. I want to register for VAT service for UK on tax settings page, but it keeps giving error: the page is asking for 3 fields

Citizen ID: Does anyone knows what is this; is this UTR of Limited company or UTR of Director of Ltd company;

Business Registration Number: Is this company registration number that is visible on companies house main page or is this UTR of limited company. It gives error if i input company registration number

VAT/GST Registration Number: This field automatically adds GB in front of it wherein my VAT registration number received few months back has no GB in it

I tried with Citizen id as Director UTR, Business Registration as Ltd Company UTR, VAT registration with and without GB. but this page gives error i.e. Invalid VAT/GST registration number

any guidance on these please