Useful links:

HMRC personal tax account login:

Sign in using Government Gateway - Government Gateway - GOV.UK

Check your NI record:

Check your National Insurance record - GOV.UK

HMRC - Setting up a payment plan:

If you cannot pay your tax bill on time: Setting up a payment plan - GOV.UK

Claiming government maternity allowance:

Maternity Allowance: How to claim - GOV.UK

Applying for child benefit:

Child Benefit: Make a claim - GOV.UK

Cancelling child benefit:

High Income Child Benefit Charge: Opt out of Child Benefit payments - GOV.UK

Claiming child tax credits:

Child Tax Credit: How to claim - GOV.UK