peter ... mate I get to ask to go there all the time though I work time to time in west africa I will NOT work in nigeria full stop because I know how unstable it is. I had a chap on my crew last month from the north of nigeria and he told me it's fine(in the north) as long as you hang out without with the right people .... the main area's to adviod is the oil rich areas of the south but it sounds you are well connected with your lot so I would go for it since you are going north .

Beware whites are targets.hope this helps.

ps I work in Oil and Gas.