UFO Sighting in Chepstow, Wales on March 17th 2016 – Lights in sky captured on camera

I was taking photos on top of the toll booths at the 1st Severn Bridge between England and Wales. I was taking some long exposure photos of the car trails and the bridge in the distance. After coming home and looking through the pics, I have noticed some lights in the sky. The photo attached is a 10 second exposure taken on my Pentax K5-II digital camera, which was on a tripod. It seems the object stayed stationary for a point then a "shadow" shows from where it moved. I was taking a HDR shot, of which I have 5 separate exposure and it shows on all. Photos taken after, do not have these lights on.