No, no very happy to hear negative points. I want the warts and all picture.
Would respectfully take issue with your assertion that King's sends more to Oxbridge than Sevenoaks in recent years. The research by the Sutton Trust (where they sought to highlight how independent schools hog Oxbridge places) shows that between 2001 to 2006 the percentage going to Oxbridge was 17.7% for Sevenoaks and 16.3% for King's. No great difference, at ranks 31 and 35 respectively, and well behind the 49% achieved by Westminster and St Paul's Girls.
In 2007 and 2008, Sevenoaks has achieved just over 15% to Oxbridge. I am not aware of King's publishing their numbers, but please let me know if you have a reference.
Finally on this point, Sevenoaks also send a growing contingent to Ivy League universtities (no doubt at least in part from their overseas students) and have a member of staff dealing exclusively with these applications, which would tend to eat into their Oxbridge percentage. Not a feature at Kings, I believe.
On the IB, I wholly agree it is not for everyone, and A-levels will suit better for a DC who already knows he/she wants to be an engineer or doctor. However it is easier for a good student to stand out. Also IMO the inevitable trend seems to point to the Universities setting their own exams a la Imperial and Cambridge (certain subjects) whilst the A-level follows the trend of the Zimbabwean Dollar
I am not convinced however about the dual teaching of IB and A-levels. They are quite different in approach, and most schools adopting the IB (eg Wellington, NLC) have concluded that the school has to be re-engineered if the IB is adopted, and it is not feasible to offer both.
Have to say that this leaves me none the wiser as to the original question which concerns the atmosphere, pastoral care and discipline at Sevenoaks.