It does sound like a made-up name, doesn't it?
No, he's EON's officially unofficial conduit through the tabloids. It became pretty obvious during shooting of SKYFALL that they use him to control the flow of information to the public. No doubt the policy came into effect after a nasty incident during filming of QUANTUM OF SOLACE when the tabloids started running stories that production had been caught up in a gang war that they had ignorantly started while filming in Panama. That wouldn't have gone down well at Pinewood because it was obvious bullshit that would have been very distressing for the families of the cast and crew, so they set Bamigboye up to control the flow of information. But somehow, whether by fault or by design, they have managed to do it in such a way that Bamigboye thinks he's an actual source and not simply being spoon-fed what EON want him to know.