I was in Hanoi a few weeks ago. We had a free day so I contacted the hotel about arranging a private car day tour. They came back and said no problem. Car would pick us up at 8am and we would see this and that. I went back and said, 8 is a bit early, any chance 9 or so?
They said it's a private tour so you can make it your own. Guide spoke perfect English. My friend is Vietnamese but had never been to Hanoi. So we did a little research and saw the major highlights and my friend and guide worked out a few places off the beaten path to see how the locals live. I just went along for the ride, but it was great . Stopped for lunch and a bit of shopping on the outskirts of the city. We had a great time.
Moral of this story, the Hotels in Hanoi are very customer service oriented. Talk to your hotel and see what they recommend along with talking to people here.
For me, it was all taken care of by the hotel, so didn't get tour company name.
Fascinating city, have fun.