anxiousdaddy - well done to your son! My son had to initially choose the 2 schools he wanted to apply to as of the 3, 2 schools had their examination on the same day. The choice was between WUS and KCJS, and he said, without hesitation, Kings. I initially thought that WUS would be a better fit for him as he is a quirky child who, if interested, will take a subject and run with it beyond the curriculum and also is very creative. However, the two schools he chose to apply to were CC and KCJS because they also offer space and a physical freedom which WUS just cannot due to its more urban location. He too got into both of the schools he applied to, and I let him make the choice. They are all good schools, and children do have a sense of what appeals to them.
DS is thriving at CC - loving every minute of it. It certainly is not very British - in fact, native British are in the minority of the student body.
Think if your son needs space, enjoys running around (does not have to necessarily be sporty - my DS certainly is not), this would be a key difference. Another key difference between WUS and CC is the access to phenomenal DT facilities (CC and KCJS have this, but not WUS) - this is what DS is REALLY keen on and another reason he wanted to apply to the schools he chose.
Good Luck in your decision. My gut feel is to let DS decide, but I guess you'd have to sway DW.