I attended a private single sex school with only 9 girls in the year - the experience continues to leave a lasting impact on me today. I was very badly bullied and constantly left out of any playtime activities. With such a small class, there was nowhere to hide and it was soul destroying to have to wander the school grounds alone for an hour every lunch trying to dodge bullies or eat my sandwiches in the toilets. The girl who instigated the bullying would have been expelled or at least disciplined in a state school but the private school was too afraid of losing the fee money so they kept bullies in the school at all costs. At the point that I was left unable to walk for six weeks after an incident on a school trip (where I was also left injured with no adult supervision on a beach for over an hour until a sixth former found me) and the school refused to say how they would keep me safe in future, my father finally admitted defeat and pulled me out in Year 7. He had kept me in that school all those years because he didn't want me to attend a mixed sex school due to his religious beliefs. The school tried blackmailing my family into making me stay in numerous ways...again because they were too afraid of losing the fees. Small class sizes were a bad sign in other ways too...within 5 years the school closed down as it wasn't financially viable (even with larger senior school classes) and all these poorly socially equipped girls were forced to attend big local state schools and colleges where they struggled to cope.
Meanwhile, I went on to be popular and very happy at two different mixed schools, one state school with a single form entry of 36 kids, one private with 100 children per year and 18 per class. There was space for me to meet people and find my tribe. There was always someone to socialise with unlike the small school. However, pastorally the state school far excelled the private school. Private schools struggle to acknowledge bullying...infact the second private school even described "a bit of bullying as character building" and financially their hands are tied. They'll keep fee payers in at all costs. They don't mind losing bursary or scholarship victims of bullying.
As a teacher, I initially started teaching in private day and public boarding schools and saw it all from the other side. Even when teachers knew certain pupils needed to be expelled and wanted that to happen, we had no support from management due to the business model.
In one school we had insanely wealthy international students who were shooting up heroin in the dorms, carrying out money lending schemes and financially extorting other students, lots of disturbing sexual behaviour and absolutely nothing was done at all, mainly because the school was financially on it's knees and the parents of the kids in question could easily donate 3 million and build a new Sports Hall rather than have their kid expelled. I left that school after a term as I knew I couldn't keep my students safe in that environment.
From there the next job I could get at short notice was in the largest, "roughest" state high school in the area. I was shocked at how much better the state school was pastorally. Kids who should be expelled were, there was no financial gain involved. There were lots of additional staff that we simply didn't have in independent schools - behaviour and learning mentors, family support workers, a big SEN department, lunchtime supervisors (as opposed to just the refectory/dining hall staff and no one overseeing playtime), chaplaincy, nurture groups and actual proper TAs and LSAs which simply didn't exist in any private school I attended or worked in.
The happiest school I attended as a child was the state school with the massive class. I'm hoping to get a job there in the next couple of years as it's only went from strength to strength and is thriving. Meanwhile the private schools I attended have closed or merged.
I don't have kids yet but I feel torn about whether I'd send them to state or one particular private school that my old good private school merged with.
I know if I sent them to the private school I'd have to put far more effort into helping them succeed socially than is normal. Forcing them to play a sport for example as the sporty kids are always the popular kids, joining the Ladies Lunch Monthly Meet and attending the Wine and Cheese and Fashion Evenings to avoid being outside of the Mum clique, putting them in from nursery age as again, it's the kids that have been there the longest that don't tend to get bullied and private schools in my experience are really crap at welcoming and supporting newcomers. I can confidently say I wouldn't have to do any of that at the good local state schools.
So that's my long winded way of saying I would never send my child to a tiny private school nor would I ever rely on a private school to actually deal with bullying. Academically, the small private school was also the worst I attended because they couldn't afford to pay decent staff so we ended up with a very old fashioned approach from teachers who were usually approaching or past retirement age, there was a lack of interactive and peer learning experiences and we had long periods of absolute boredom. The school also attracted teaching staff who had moved there because they actually couldn't manage a large class and had poor behaviour management skills which then had the knock on effect of allowing bullying to thrive. If you've got a good state school near you, then seriously, seriously consider it. It would be a no brained for me.