Anyone from Hounslow to Sutton/WCGS?
Hounslow to Sutton is over 20 miles through town or 40 miles on M25, up to two hours on public transport in the morning. Would you really want your DS to spend 4 hours a day commuting to/from school, and that's before he gets on with his 1-1.5 hours homework a night, having to get up probably about 5am? Have you considered moving?
Quicker by train. No less daft, though, when you take a deep breath and think about it. At least the train (or any public transport) option would give flexibility when taking part in after-school activities, meeting up with friends at the weekend etc. Less important, of course, if you regard school just as somewhere you send your child to have lessons for five hours a day, rather than a community.