Glow Plug light flashing intermittently..........

I only noticed this yesterday, and its very random and intermittent when it does it too

First noticed it when id got home in the morning, had to park for about 5 mins, then back in and hook my trailer on. Id driven about half hour before stopping and moving again. Car starts great (has done pretty much since i had the glow plugs replaced), but while it was idling away and for a few mins of driving the glow plug light flashes. For the rest of the time i was driving around it stopped, but did it again later in the arvo when i had to go out again

As i said, it seems to start up fine and runs fine, and the glow plugs were replaced on my last service (roughly 5000km ago).

Is it something to worry about? I know it'll probably do it again to me today when i go out........