Hi,
Which camp are you staying in? L Manze?
You'll also need malaria tablets, and possibly a yellow fever jab and certificate, depending on your itinerary. See a travel clinic or GP for professional advice.
As to your list, I'd also add the following -
spare batteries for cameras/torch; (a head torch might be handy - you won't really need a torch in camp as you will be escorted at night by a maasai, but you might need one in your tent, depending on level of electricity available.)
spare memory cards;
hand wipes;
liquid soap for hand/ clothes washing;
you may also want long-sleeved and -legged clothes to cover arms and ankles in case insect aren't deterred by repellant or in case sun too strong for your skin.
I'd keep most of this stuff in your carry-on luggage as you will probably need it in transit from the airstrip to the camp. I have seen people burn in the 3 hour drive (it was an impromptu game drive- it would probably have taken 30 minutes direct).
Don't think you'll need many books, but they won't go amiss. I also tend to take deflated footballs with pumps, which are very welcome by the staff or local schools.
(www.footballs4fun.org)
Doubt you'll need waterproofs or jumpers. Maybe a thin fleece.