Traffic light Gatso cameras take three photos, one with the vehicle in front of the stop line, one with the vehicle over the stop line and one showing the vehicle fully across the junction, the last being to show that the vehicle didn’t stop once over the line. All photos will show the red light, the speed the vehicle was travelling, and the exact time.
Crossing an amber light is not an offence. On that basis you should be OK, and it was the Merc who was flashed.
The police have to serve a Notice of Intended Prosecution on the registered keeper of the vehicle within 14 days so you should know fairly soon. Also just because the camera flashed is no guarantee it was in operation.