I have a nanny two days a week for 1:1 care of my 2 year old. We are planning to ask her to also look after my sister’s 1 year old on one of those days. The two are like sisters and we are totally flexible on whether they will be at ours/theirs or out and about etc. Can anyone guide me on how much more we should expect to pay for two vs 1; currently she’s on £12.50 an hour after tax. TIA 🙏