Hi - Can you help me with my 2007 Fiesta 1.25 Zetec issue.

Recently after a few minutes of driving I hear a sound like the door locking sound and I see both the left and right indicator lights on the dashboard flash once together. I've checked the doors and they are not locking so I'm not sure what the sound actually is. At first I thought I was imagining it, but it has happened a few times now. Seems to happen a few minutes into the journey.
Does anyone know what is causing this and should I be worried?
Thanks!