In the last year of the 3 paper exam, (2014 entry), DS2 got 378.962. In year 4, he had been selected to attend weekly after school maths sessions at WHSG along with a boy from another local primary (the Southend / Westcliff grammar schools are - or at least were, when our 3 were at primary school - pretty good with outreach stuff) and in year 5, attended actual maths lessons with one of the year 7 classes there. (When DD joined the school for 6th form, some of the girls remembered 'the boy in the red jumper who sat at the back of the class'

). However, he was a bit of an outlier at primary school and I think this both gave the school something to tick off on their NACE form and his teacher a bit of a rest. Also, DS2 was absolutely sure that nothing that he had done on the year 7 classes was
necessary for the CSSE test.
DD, 2 years older, got 290.xx in the CSSE test, spent a year doing very well at a local 'failing' comp, passed an in-year test for SHSG and got 4A* 6A or their numerical equivalents (sat GCSEs in the year when only Maths and Englisg changed).