Hi there folks - am a key stage 2 teacher really so please double check my 'facts' for any KS1 info!
At the end of year 2, they are meant to be a level 2, year 6 a level 4 - that is the 'average'.
They are also meant to gain around half a level each year......so working back, at the end of reception they 'should' be a level 1.
W means working towards level 1 (ie just below level 1)
MaddieMo and Jimjams - in your DS' statement, are the 'disapplied from the national curriculum'? If so, they will definitely not do SATs. If they are entitled to 'access to the full national curriculum' ie do what the other kids do in all the lessons, then they will do SATs UNLESS THEY ARE WORKING BELOW THE LEVELS OF THE TESTS.
For example, in our mainstream school, pupils at year 6 who their teachers judge to be working below level 3 (and we have some every year) do not do the tests/tasks. And you do not need special permission for this other than the teachers putting a pretty standard form into the LEA in the spring term of the SATs year. They pretty much always get agreed with.
HTH