Hi all,
The St Olave's mock tests are open for registration now. See
http://www.saintolaves.net/pamocktests to register.
I'm a St Olave's parent (and a teacher elsewhere), and I helped invigilate at the tests last year. The mock tests are run by the St Olave's PA in close partnership with the school, to ensure that they are as close to the real thing as possible, not only in the content of the Stage 1 SET paper but in every aspect of organisation, instruction-giving etc., so the children - boys and girls - get a very close idea of what the real thing would be like.
The exams are marked professionally, and parents get detailed feedback in each subject area plus percentile rankings within the cohort, so you should get a firm idea as to how your child may perform against his / her peers in the real thing.
The PA also offer free places to those children who qualify for Free School Meals.
I hope that was helpful.