I think you did the right thing. You were polite, and got your point through without hurting the neighbor's feelings, and that's what matters.

In the area we live in, the houses are close together too. I'd say about 15 feet between each house too. Our next door neighbors on one side are a couple with 3 dogs and two parakeets. I can hear their parakeets chitter chattering when both of our windows are open, but its very faint and sounds nice. They only do it for like 15 minutes then quiet down. Their dogs.............2 of them don't bark *at all*, and their 3rd addition barks occasionally, but they are responsible enough to keep him inside when he does. No disturbance from that side.

On the other side, we have a family, we about 5 kids..........older kids in their teens, maybe some in their early 20s. The kids are *never* at home, but they come home at like 1-2 am when we're sleeping, and used to chat OUTSIDE with their friends. It was ANNOYING to be woken up by the voices of teens outside. What we did was we wrote a letter, and put it in their mail box. The next day they came to apologize and we've never heard them ever since. I'm glad we have such nice neighbors. The rest of the neighborhood is quiet, not many kids, only one annoying dog on the other side of the road that can bark all night long. We haven't told them anything *yet*. Can't figure out how.