Talk first, then write down what needs to change and by when. gov.uk expects an employer to discuss a conduct or performance problem informally before anything formal, and to have written disciplinary rules that follow the Acas Code of Practice (the Labour Relations Agency code in Northern Ireland); a nanny can raise a grievance with you, and may bring a companion to a formal meeting.
If you booked the nanny through Locufy and rate them under four stars, you are asked whether to send it to them first; we follow it through. Then you review.
Follow the notice in the contract: after a month in the job an employee must give at least a week's notice, and dismissing without proper notice is wrongful dismissal, so act fairly and keep records. Final pay includes wages owed and any untaken statutory holiday, even after gross misconduct; give the nanny a P45 and report the leaving date to HMRC through payroll. The Acas helpline (0300 123 1100) advises employers in England, Scotland and Wales.
Then you are a customer, not an employer: the agency or the self-employed nanny is a trader who must use reasonable care and skill under section 49 of the Consumer Rights Act 2015. A money claim against them can go to small claims — up to £10,000 in England and Wales, £5,000 under simple procedure in Scotland, £5,000 in Northern Ireland.