wouldn't it be better to be placed in the set which the results give without having got there by help? rather than artificially getting into one above and then struggling? would be horrible to feel out of ones depth from the off for the sake of a temporarily higher set I'd've thought.
I think this is a really important point. I have 2 sons at GSs in Essex. Recently, 1 was dropped a set in Maths which for him was a bit demoralising. He was struggling and this did make him unhappy. Now he is in a lower set he is really thriving.
Remember these are selective schools. By definition it means that the least able in a year group is still ahead of those who did not get in. (I know it's not that simple but you get my drift?)
Don't worry about not being in the top set. What is more important is that your child is in the right group.