通知迟到并询问签到地点

Dear School Office,

[Child's name] in [Year/class] will arrive late on [date] because of [brief reason]. We expect to reach school at approximately [time], although this may change. [Adult's name] will bring [Child] to school. Could you confirm where we should report on arrival and whether we need to complete a late-arrival entry? We will use the school's required attendance channel as well and update you if the arrival time changes substantially.

Kind regards,
[Parent's name]