Sounds like you have a MY03. I had a late registered GT4 on an 06 plate but it was still a MY03 and had the plastic heater knobs. Its sounds like you have one of the last 2006 MY03's.........
Yes, needless to say, this was what I was getting at. Having seen the pics, its confirmed that you have a pre-facelift 06 car so wouldn't have the LEDs.
Oh, and welcome to the site!