Yes, so one of those schools that attracts people in with the funding for early years, but over half don't carry on into the main school.
For me, 16 in a year group would worry me. The chances of that being 8 boys and 8 girls is unlikely - in some year groups they might be only 3 or 4 of one gender - def one to check up on. They will struggle to get a hockey or rugby team out. And so small can make friendship issues more likely....fewer people to be friends with or find people you click with.
What do you think you'd be paying for apart from the small class sizes? Are there great facilities? Are there lots of specialist teachers higher up then school? Does it have something your DC especially need such as SEN provision or a music specialism which is attracting you?
Just dig a bit deeper into all of these things. Send a long list of Qs to ascertain the breakdown of girls and boys in each year group, how much turn over there is amongst the kids through the school and stuff about specialist teachers, facilities and match involvement wig our schools.
It sounds like one of the small Preps round here, which are at the lower end of the fee structure......very small. I've known people v pleased with their experience....nurturing, cosy, family feel. Those I've known have entered late from schools where the kids have struggled and then found the cosy, small atmosphere really positive. Those kids haven't been very academic and the schools haven't been specially academic either, but they have been good for those families. Plus, TBH, they would have struggled to afford more.
It all depends on if it meets your requirements from a school. Could be fantastic and pretty good value for money.