Prompted by posts elsewhere on the board, I actually rang the secondary school my DD will be going to in Sept, to ask how important the SATs results are in 'streaming' the kids when they start in September.
It turns out that, along with the teacher assessments and CAT (?) they are important.
I asked the Yr7 tutor the direct question about whether I should coach my child so they get the best results possible, or whether I should leave the school to do it, so the results are a reasonable reflection of what she is capable of without additional help, but he said it is a matter of personal choice.
Have gone from being quite relaxed to now a bit flummoxed.