I would suggest that in addition try the gabbitas school information website (I don't know how to post links on here?).
It
depends whether you want a same sex or mixed school and whether your child has any siblings you would later want them to attend the same school too. Boarding fees vary greatly from a few thousand to as much as £10,000 a term.
I also agree that 6 years is a little young. I boarded from age 11 to 18 years first at a girls school then a mixed school, and my brother was at mixed school from 7 years, he hated it and was very homesick and alone the first few years. I later joined him at the same school when I was 13, which I didn't like as much as the single sex girls school. It did affect our relationship with our parents in that we were not as close to them from as we were always at school, but we have since gained some of the closeness back, but sometimes if parents careers demand it is cannot be helped.
But whatever you decide you need to vet vet vet these schools and vet again - do not be swayed by the Englishness of the brochures...you know pictures of chapels and rolling hills!!! They are not all equal and some are not as academic as the brochures suggest. Not meaning to alarm you but just because you are paying fees does not mean that the drugs and teenage pregnancies, abuse don't occur, they still exist you just don't hear about them. Some schools are very traditional some more religious it depends on your and your husband's goals for your child, is it purely academic, or sports, or music (Winchester, Westminster Schools) or do you just want your son to have a happy well rounded childhood or are you hoping he will be the next Obama
in which case you may want a Public school like Harrow or even Eton for character building and producing of leaders of tomorrow and a direct springboard to Oxford and Cambridge, though obviously these schools are expensive and may have long waiting lists so if you are interested in these types of Public schools you would need to express your interest sooner rather than later.
All these factors will determine your choice. I would say if possible keep your son home until he is 11 prepare him and encourage him to be strong, confident and fearless then if you are still sure you want home to go he can join Year 1 at 11 years old. Just remember these schools are business and while many do a great job at teaching and raising children they can never nurture and love your child like you but they can get you the academic (or other) results.
As much as I had a reasonably fun time, would I send my children? No, especially without a sibling.