Thanks Tyyrlym. He never used to tolerate being handled or having anyone too close to him, but recently he's become a lot more tame. He'll sit in my hand or wander about the sofa while I'm watching tv beside him. Last night he climbed up my sleeve and I had a job getting him back down again. All in all he still doesn't like being handled too much although he will let me stroke under his chin.
If I go up to the tank and call his name usually he'll come out of his cave and up to the front of the glass asking out. When I talk to him he looks right up at my face almost as if he can understand what's being said and has a really comical expression.
I'm always quite wary when I'm handling him though - if they get a sudden shock they can drop their tails.