I look after several girls who are at WH and have been with me since they were babies. My daughter also went to SAHS.
The assessment is not 'testing' to see what they know, but assessment for their potential to learn. Mums are always trying to find out what happens and no one has a good idea!
I believe ( as the girls were very sketchy about what they did and remembered ) they are asked to pick out their name, write it if they can - looking for pencil control, cut with scissors, - (the 4 year old couldn't!) Listen to a story, ask and answer question confidently, look at the teacher when you speak to them, - what do you think happened next type thing, puzzles, and not a lot else! It's not very long, they only go once, no being called back, as there are so many for the 40 places.
There is a waiting list and places get filled as people move out or away for various reasons. They also take a 4 more again for year 1 and year 2 and you are given the chance to try again by staying on the list of continuing interest.
The girls were not prepared in anyway, they had nursery education at home with their childminder, who collects them and still looks after them. They always did lots of sticking, cutting, stories, puppet and role play, learning through lots of outside experiences. My colleagues daughter was in a nursery from 6 months old, but didn't get in, they assumed she would, so were devastated as they were a bit short sighted in not applying for state schools so had no real back up plan.
There is a huge difference in the age range as some will have turned 4 in Sept 09 and be 4+4months, and the others, summer born, only 3 years +5 months, nearly a years difference, but one of the girls was not 4 until August and she is actually the brighter one!
The assessments are being rescheduled due to the snow, which is interesting, because Reception, Yr 1 and 2 don't go back to Monday, to allow the school to be used for the assessment days, I wonder how they will mange that!
Good luck, if your daughter gets in she will love it, it is such a lovely school and learning environment.