How do I make a Child Benefit claim in London and does the process differ from the rest of the UK?

There is no separate London scheme: Child Benefit uses the same UK rules and application process. You can usually claim through the Child Benefit service on GOV.UK, or use form CH2 if needed; claims can generally be backdated by up to three months. The benefit may also protect National Insurance credits for the person caring for the child. If you or your partner has adjusted net income above the relevant threshold, the High Income Child Benefit Charge may apply, so check the current GOV.UK guidance for your circumstances.