Research tells me that this is a female Namibian Rock Agama.
Found on our second campsite at the Solitaire Guest Farm which was considerably more pleasing than the first and even had a swimming pool looking over the Namib Naukluft Park. A shame that we were only staying the one night.
A wander around the campsite revealed this lovely lizard. She obliged by posing on the tree trunk and allowing me this capture.