If your chosen companion is not available at the time proposed for the meeting, you can ask the employer to postpone the meeting to another time. Your proposal must be accepted by the employer if it is for a time within 5 working days of the original hearing which is convenient for all the attendees.
Don't forget that your chosen companion must be a work colleague, but this can include a union representative working for the same overall employer, whether at the same site or establishment or not.
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