"It is an interesting point though surely that children may not always be entirely honest about how they feel about boarding school. Worth exploring maybe?They will be aware, for example, of the sacrifices their parents are making for them to go there and may also accept what they hear of the huge benefits they are receiving which will be great for their future without thinking, yes, but shouldn't I be happy now?"
That is EXACTLY my DH's experience, and to a more limited extent, my own.
Both of us have loving parents who would see themselves as perceptive and in touch with their children.
DH, when his parents returned from abroad and removed his sister from boarding school but not him, said, in essence, 'We are making sacrifices to send you to boarding school, it is a great opportunity for you and you have always said you are happy.' UIt was NEVER said explicitly, but in that kind of 'taken for granted' way that i so difficult for a child to respond to.
In my case, the acknowledgement was always on the table: 'This is the way you can get the education that you need. We know that you might be 'happier' at home but in the long run that better education is worth it.' I am still grateful for the ducation, without ever having been able to ay that I was truly 'happy' at school. Educationally, it was great. Socially, as someone from a very different background, age accelerated and socially awkward ... less so. But then the same might well have been true had I attended the local ex secondary modern comp that was the only alternative. I'm not sure whether my siblings, who attended the latter, would say that they were truly happy at school either.
As I have said above, though, I understand that sometimes the balance of 'boarding / non boarding' falls towards the boarding side for some families some of the time.