Ds is on a substantial bursary. I have found amongst friends an attitude of 'how did you manage that' yet they wouldn't dream of asking or applying because they assume things about bursary assistance.
Each school has very different criteria for allocating bursaries, the only similarity being that they may use a standardised form. After that, it all depends what their agreed policy is.
For example, currently ds is at a prep school on a 70% bursary, 10 miles down the road, with exactly the same financial declaration, he was offered 25%.
The bursary middleclass ds is on is defined by the school. If their policy is that applications are open to all then she is as allowed as the next person to apply and have the school decide according to their published criteria, it can't become a problem for other parents in the country that she qualified for a particular school on a particular income according to a particular policy!
That would be like me saying ' I'm applying to x senior school for my ds and its middleclass fault that x senior school has a different policy to her ds school'
There is no uniform policy around bursaries, so one school could have a policy whereby they only offer them to very set criteria (tends to be 'foundation' schools' ) or they could have a policy which allows supposedly 'well off' parents to apply for their style of education. Only the school decides who does and who doesn't qualify, not the parents.
In the op case, it also depends on her dd schools policy for financial assistance to existing pupils and how big theit financialpot is and even how many other parents choose to apply for assistance.
I didn't play any kind of game to get ds his bursary, everybody is welcome to fill in the forms and let each individual school decide.