I live in the Trafford catchment and my children currently attend a lovely (not private) state primary school in the area.
I also have a child in that academic year. From the parents conversations at school most are aiming for AGSB as that is classed as the best for boys, followed closely by MGS. Then Sale Grammar then Stretford or private. Ambrose is classed as best for those with a catholic persuasion, followed by St Beads.
Every child who is aiming for grammar with a realistic prospect of success has had some form of tutoring. Most children are privately tutored or attend Kumon/Explore learning. Also to add to the fact that state schools don't prepare - those in the hale/altrincham area do. My DC's school puts on extra lessons for children wishing to partake in grammar school entrance exams.
I opted out for personal reasons relating to my DC. I have been treated like a pariah! I know that the state schools in my catchment are amazing and I am looking forward to DC starting there. I am also aware that my DC would have floundered under that pressure, so AGSB would not have been the right choice for my child.
Tutors currently range from £20 for bog standard - those with a record of successfully tutoring children into certain schools charge up to £40 per session.
I should warn those that move specifically - it starts early. Our infant school expect students to be a level above national average in maths/English - just being on target isn't enough.
Also last year, during conversations about tutors due to having a child in year 5, I was advised to find a tutor for my reception child, when they enter year 5, as the best ones are already fully booked. I did enquire with one tutor who advised that to gain private lessons, my reception (aged 4) child, would be on a waiting list, to be tutored when they enter year 5. I will be advised in year 3 as to the position on said waiting list.
It's fucking crazy actually and I would prefer to live in an area where children just went from a local primary to the local secondary.