I'm a babysitter and regularly babysit for a couple and their two kids. They're off out tonight and have asked me to babysit but also to watch one of their friends children (who is going out with them) as well.
They're all around 10 and the kids get on well.
Should I be charging more or charging a separate invoice to the other family as technically I'm providing a service for two families at the same time? I charge £12ph.