When are the SATs for KS1 children?

[ThomasTankEngine]

.....as I'd like to book a holiday an avoid them.

Or should I try and go on holiday at the same time?

Loudlass I can understand you being angry but the school has nothing to gain and much to lose by "falsifying" pupil numbers. Budgets are set on the number of children attending so to effectively reduce the reported numbers by more than 50 children is financial suicide.
Schools can request that children with SEN are "disapplied" from the SATS and she should not have been entered. I know some schools who include SEN children in the process (so they aren't seen as different by their classmates) but usually they are given a task at their own level.

Loudlass - the published number of pupils currently attending is set on a day in January. The data in your prospectus would be from last January and so would include last years year 6 and not this years reception children. Also if your school is like ours and has an intake every term then every year the Easter intake is missing from this data. You'll find that most schools have a discrepancy between the data and the actual numbers attending a school.

No school would understate numbers! 5 children would mean a budget loss of about £20K (e.g. a full time TA or NQT)! PLASC (Pupil Level Annual School Census) day occurs in mid January and counts all children registered at state schools. At our school, it is a very important day as we have lots of service children and one or two leaving just before that day can cost us dear! We always hope for a net increase at the beginning of the Spring Term!