As jamlcj and ArtGeco pointed out, you need to change the UVB light every 6 months. If it's one of those heat\UVB combo compacts (like the T-Rex) it should last longer, but since you've got a full year with no growth - inspite the proper diet - I'd consider the hip. that the lighting is malfunctioning.
Have you tried replacing it before?
Also, has Gus ever enjoyed the wonders of direct sunlight? You could try that during the summer months.
Have you tried replacing it before?
Also, has Gus ever enjoyed the wonders of direct sunlight? You could try that during the summer months.