I was tutored for the entrance exam for a selective girls school. Can't say which one for fear of outing myself, but it was a regional single sex school which usually ranks fairly high in the results tables. My parents had 2 reasons for tutoring I think: firstly because I'd missed a fair amount of school due to illness; and secondly because neither of them were privately educated and I think they wanted some external validation that it was worth putting me through the exam.
I have quite fond memories of my tutor, who was a lovely retired teacher. I don't think I had many sessions with him, maybe 8, and it certainly didn't feel like cramming. Mostly I remember doing past papers and then he would pick up on things I didn't know. My clearest memory was that he had to teach me long division which I initially thought I must have missed at school when I was ill, but later discovered that no-one in my class knew how to do it, which is pretty poor at 10/11.
I distinctly recall that my class teacher was very dismissive of me sitting the entrance exam and told my parents that it was better to be at the top of X school (the comprehensive that my primary fed to) than the bottom of Y school. My mum didn't actually tell me this until I got my GCSE results at the independent school and was in the top 5% of my year (she may have felt a tiny bit smug).
Quite a few of the girls that I was at school with had been in private education before 11, either at the same school or at a local prep school, but it wasn't the norm and I suspect that a lot of other kids had had some form of tutoring. However I can only think of a few girls who really seemed to struggle as they got older, to the point where you did wonder whether they had been crammed for the entrance exam. And they did seem to be some of
the ones who had very wealthy parents (I was on an assisted place, sacrifices were made for me to have even limited tutoring).
I certainly didn't feel that I struggled at school, I had no external tutoring after I passed the entrance exam and was in the top set for every streamed subject apart from maths. I mostly enjoyed school and made some lifelong friends (I had lunch with one last week). The only thing that made me feel inferior was that my parents were pretty skint compared to a lot of the kids there, I never felt that academically I couldn't cut it.