What area did you come from when you got flashed? can you prove the time you left up to the time you were flashed? witness statements / receipts as evidence.
It has happened to me in the past also nothing transpired with me either.
They are turning all of those type of speed camera's of at the end of the month in the West Mids at the end of this month, they say it's because they are to expensive using wet film !.
I got the double flash from the camera that was facing me, on the right hand side of the road.
May be it was meant for someone passing in the opposite direction, I checked in the mirror but they seemed to be a long way off.
I guess I'll just have to wait for a couple of weeks and hope for the best.