I am an Abbey Junior School mum, and highly recommend it. It is a very happy school with happy girls and great facilities. It is very popular, and I think that many year groups are full with waiting lists. Few girls leave unless moving away.
There are plenty of-in fact I'd say an abundance of- "sensitive" children at the school, all well catered for because the pastoral care is great. I think that it nurtures and develops independence and confidence in all girls, as well as providing both academic stretch and support for those who need it. It is good for girls who will benefit from a structured day, but there is an amazing array of optional, free, lunchtime clubs for all interests (like sports, music, art, science, languages) as well as paid-for before and after school clubs like speech and drama, dance, judo. We like the fact that the girls get a PE or gym lesson every day.
As for the selfish ruthless girls (who are no doubt at all schools) I imagine that those qualities are a product of their upbringing and home environment, and Abbey girls are encouraged to be kind and considerate. Abbey girls are taught to look out for each other, and for others-on Friday they had the annual pupils only Charity afternoon, organised by, run by and attended by the girls-great fun.
The journey is a consideration-I gather you might be Maidenhead side of Reading-the traffic into Reading is awful, and depending on the age of your girl there is a coach service worth considering.
I have no experience of the Senior School, but the Head Mrs Stanley is very nice, and the ability to go straight through is a bonus.