With state schools in Cornwall, it's usual for children to go their nearest school, as others have said, due to the distances involved. Most state schools tend to have a very mixed catchment in all sorts of ways, and the associated problems that come with this. Some pupils will have very low or limited aspirations for themselves, and this can lead to a culture of low aspiration in some cases.
If you were happy for both your DH and your child to have a bit of a commute, you could live somewhere with a train station (e.g. Lostwithiel?) and then commuting to one of the Grammar Schools in Plymouth might be an option. Obviously these are competitive to get into, and you couldn't assume your child would get a place. Living a long way from school might also be difficult socially, and if you have more than one child, it might be an issue that this would not suit all of them.
I know a few pupils at Fowey school who have had issues with bullying. It is an improving school, apparently, but I don't think it would be a very attractive choice.
When looking at where to move for particular schools, it's worth bearing in mind that Cornwall Council has "priority admission areas" for each school. This is where they supply buses etc for each school, and they're designed so that every child has an accessible school, but not every child would necessarily go to their closest school. This might also be relevant to school admissions.