Violetbloom - it would depend on the teacher assessment. If all other pieces of evidence pointed towards a 3, then she would still be a 3, whether she achieved the mark required to award the level 3 or not.
If she didn't achieve it, and all other evidence pointed towards a 2a, then there would be a huge question mark over why the teacher chose the wrong test in the first place.
TeamEdward, I'm sorry, but I think you've got this wrong. I woul ring an assessment advisor to check - children should statutorily sit one test only, and your teacher assessment could be called into question if you give two. As you yourself said, if the child achieved the level 3, it wouldn't be admissable anyway, since the evidence wouldn't be there to back it up. And if you did have level 3 evidence to back it up, why give them the level 2 test in the first place? It flies in the face of the whole point of teacher assessment at key stage 1.
Cortina, I have spoken to you many times regarding this issue. I have no idea where your notion of "Most primary schools seem to have a set number of children that work at each ability table?" comes from - it isn't true, and you won't find any teachers on here who work like that. Primary school furniture usually lends itself to being pushed around and together, and it's easy to make bigger tabes.
I have also suggested to you since the teacher doesn't seem to work with the top group ever, that the worksheets they are given and left to get on with are not extension work, as you describe, but work to keep them occupied - this isn't teaching, and as such I doubt there will be any 'pulling away' in your dc's class. (Especially if they are all in neat groups of 6.)
My advice would be to move your dc and to stop telling me what happens in 'most schools'!