The trial ended in June but definitely (in our case) included a big delta surge.
Daily LFTs as part of the trial weren't allowed for confirmed contacts of delta variant cases until around 3rd June.
These participation pauses occurred at 14 schools, 5 due to school capacity issues, 6 due to school or public health agency concern about Delta variant, and 3 due to public health concern about cases in the school as a result of transmission in the community.
This is a problem when you are only looking at 63 daily LFT schools actually having cases to contact trace in the first place. So if 14 of them duck out of the trial when they don't have enough testing capacity or there are concerns about how riddled the school is with covid, this casts doubt on the legitimacy of your data in a high infection rate situation.