Paul,
I think the shaping of the top (for the candle) could have been shaped a little better, but I love the concept of using old timbers like this. Keeping the history of the wood alive in the final piece. You've not just left some of the old outer surface visible, but I can also see charring from some sort of fire, the places where you've set in the marbles look like some sort of old nail or insect hole.
You've certainly made this piece of timber sit up and say 'I have a story to tell'.