thank you all for such quick responses. We do have visibility of what he is doing and we check the homework he brings and see the comments she has made etc. This work all seems fine, its just when he sits the timed paper he scores low - we are aiming at 1 a day but have recently stopped. The low scores are affecting his confidence and as people here have suggested i've started sitting with him and going through his weaker subjects. When I explain stuff he takes it in but he just seems to make so many careless mistakes!
He did sit the mock exam at WCGS and he came out saying it was easy - we'll see tomorrow how 'easy' it really was tomorrow!
The tutor is getting 5-10 kids a year into grammer schools. We personally know a few parents that have sent their kids to this lady and who's children are now at these schools.