Iveco 75 e15 glow plug light?

Hi there
I have a 2000 iveco horsebox. When i first turn ignition the glow plug light flashes and continues to do so for a lengthy period of time. Then when i attempt to start the lorry it is reluctant to start. The light continues to flash for some time. However, once it has been initially started and is warmed up it starts fine. I just wondered if this lorry has glow plugs and if it would be them that is causing this problem. It is booked in for a service and test in 2 weeks time. However, i am concerned it will pack in before this time ?!