The school had budgeted for support staff being part of the Mutual Fund for the year but had not realised that the school had not requested them to be included as part of the premium. Can the school join midway through the year?

Yes, the school can join midway through the year whether this is to include additional cover or to join the scheme completely. However, the school may be required to pay the 7% joining fee depending if they were not part of the scheme the previous year and that the premium will be pro-rated from the point of joining the scheme.