I would suggest scrimming down the two lights that you have on the brick pillars (also the lights under the trees) if you want to stay with the 15 sec shutter. You can buy high density wire mesh from a local hardware store and place that over the lights which should take it down a few f stops.
Also you caught your flash in the window near your front door of the first pic and the passenger window of the car in the second one
Try either moving your Benzo closer to the camera for a foreground element or zooming in a bit.
Experimenting is what its all about. Thats what I do probably 90% of the time when Im not shooting for other people.