In my humble opinion, the previous poster is correct in saying that a v. good score in the VR is very desirable but I disagree with the 90% mark and also, you do not need to have a v. good English AND Maths to get in if you've scored highly in VR.
As a rule-of-thumb, you need to score 82%+ overall approx. to get into CCHS. (that's from recent personal experience). I appreciate that they standardise scores so it's not quite as simple as taking 25% of your child’s Maths paper, 25% of English and 50% of VR but it's a close enough approximation.
If you get a score in the low 80s in VR, then you need to be getting in the low 80s or better in both English and Maths. By getting a high score in VR you can afford to have a weak English or Maths paper as, VR is worth double or 50% of the marks overall. A for instance is 87% VR, 82% English and 72% Maths gets you in. My daughter got 68% in Maths and got in comfortably.
The other thing I'm not sure about is that both Maths and English are always hard. I understood it that the papers alternate every year. So last year was a hard Maths and this year is scheduled to be a hard English paper. The Maths and English papers are set by the different grammar school heads in Essex on a rotating basis. I can say that with my children, the papers worked out this way and in doing all the past papers that did seem to be the pattern. It's just an opinion though. Does anyone else subscribe to this?
Not sure about the years rotating but you could be right. I would still say aim high on the VR. My daughter too got high 60's in the maths but did well in the VR and OK in the English. When she was doing the practice papers she was getting 85%+ in the maths papers and 80%+ in English so it shows you how different it can be on the day. At least with the VR the NFER Nelson practice papers you know they are the people that set the VR on the day so you can get to know the patterns/types of problem questions that will come up. Good luck to anyone trying this year - I wish you all success!