Thanks all - if I can create that effect in what really was a few minutes, anyone can.
Another point I would make about wood, is that you rarely see wood that is completely uniform in colour. Again, a few rubs of a pencil can add some shading on top of which you can then add grain effect.. sometimes the shading and colour variation is enough to trick the eye, without the need for "grain" on top.
James - hope this works for you, just give it a try! For the amount of use you can get from each pencil over time, they work out really really cheap. And also if you can get satisfactory results to your eye, without needing to coat with oils, then the work dries quicker too.
As with most modelling techniques, it is whatever suits you best
