Paragraph 64 of the exclusions guidance makes it clear that the headteacher has a duty to write to the family of an excluded young person to confirm the exclusion. The headteacher must do this "without delay".
It's also important to note that in line with paragraph 63 of the exclusions guidance, whenever a headteacher suspends or permanently excludes a pupil they must, without delay, notify parents of the period of the suspension or permanent exclusion and the reason(s) for it. This initial notification should be in person or by telephone as this would allow parents to ask any initial questions or raise concerns directly with the headteacher.
Answer the question, Did the headteacher write to the family to confirm the exclusion?
If the answer is no, consider using the Suggested Wording document: Argument to the governing board: School failed to provide an exclusion letter