Thanks RLS. I woke up the other morning and he was very cold to the touch as the viv had dropped to about 16deg.
No i dont have any hideouts high up but i do have a few further down which he does like to hide in. Also about 4/5 plants to hide in. I will look into cork tubes tho.
At the moment i am heating the viv with a red incandescent bulb in a bulb holder just above. Do cresteds definitely not see the red light? Because i have it on 24/7 at the moment. The reason i ask is bacause their pupils do adjust when they look into it.