Schools like St Pauls, Westminster are specifically looking for candidates who would interview well 7 yrs hence at Oxbridge??
Gosh really? My eldest daughter who is at a super selective senior school (with a very high oxbridge success rate) was a dreadful, dreadful interviewee at age 11. ( I know as I sat in on one of her interviews for a scholarship place and my toes curled for the entire 30 minutes) She gave nothing but semi comprehensible one word answers. It was one of the most embarrassing half hours of my life, genuinely. I know she could answer the questions, but she got terrified and tongue tied and it was truly, truly awful. Had I not seen it I would never have believed it.
Despite this she was offered a 50% scholarship, based entirely on her exam results. Luckily after a few years at this school she has changed beyond recognition and could now out-interview almost anyone. Maturity and confidence have made the difference. So, I wouldn't panic too much if your child is academic but is not great at interviews, they are important, but no school will give a place to a low scoring child who is charming and articulate over an academic one who is nervous and quiet. Even top schools have many, many quiet children.