Late collection - when to call and when to charge?

[mogs0]

How long after a child is supposed to be collected do you phone parent? Also, if you charge full hours, at what point do you charge another hour?

I'd call after five minutes if I'd heard nothing.

I charge £5 for every 15 minutes late, with a minimum charge of £5 - I'll give perhaps 5 minutes leeway on the first occasion but then no more. If you're 6 minutes late, you get charged £5. If you're 16 minutes late, it's £10 (and so on)