Aip
You wont find anything on the nama website,next time you are in lagos airport, walk accross the road from MMA2 terminal to Nama headquarters (nigeria airspace management agency) tell them at the gate you are a pilot going to the AIS office. It will cost you 180 usd for the cd and this gives you a year worth of updates for . They update it every 4months with permanent stuff and ammendments if any within that period. The guys are friendly and professional.They always complain that they dont get many pilot visits. You could also fill in the facilities and service complaint form (controllers, navaids, lights etc) they usually get very little feed back from pilots who seem to prefer bitching about stuff on the radio or internet forums.