Shibu means branch, perhaps designating something less than a full dojo. Sometimes in English, a study group, denoting that the instructor doesn't have full teaching credentials.
Dojo simply mean place of exercise. A dojo can be a movable feast, as it is primarily the people, not the physical location. There are dojo in Japan that train in 2-3 different places each week. the name remains the same, but the location is different.
So I practice in a number of different dojo - giant facilities, purpose built 'dojo', outdoors, etc.
Lance Gatling ガトリング
Tokyo 東京
Long as we're making up titles, call me 'The Duke of Earl'