回复：又见dztang,顶一把先.再问一个关于内罗毕的个问题

It's the right choice to use London as the hub to
Africa. I used http://www.airtreks.com for my
previous trip. But, it seems that it make more economical sense if you have more destinations
to use their services.

It's likely all the agents will eventually use
British Airway, Air France, and Kenya Airway to get you to Nairobi. Check out http://www.tokenya.com
to see if you can get a better deal. I have been
looking for some good travel agents based in London
to find better deals, so far, have no success.
So, I really have little advice for you on this.

Once you are in Kenya and/or Tanzania, a good
service you can go for is "Tara Travel", http://www.zaratravel.com. It's highly recommended.

Good luck!