That's a difficult one. The ribbon looks like the Queen's Sudan Medal (although the yellow half is on the right) and the crown, having two dipped arches looks British (St. Edward's Crown?), rather than the four arches common in many European crowns. The cypher 'N' doesn't correspond to any British royal name, though it could be the cypher of a British army unit. Overall, it doesn't look very British (more Belgian) and is probably unofficial, as you suggest.