Thanks guys for your help and again sorry for hijacking the thread.
I found after more trial and error that even though i had the piece of 4 x 2 outside of the target line i was still managing to swing slightly (ever so slightly) outside in. I moved the timber even closer and i started hitting it on the way down again (timber placed so the clubhead only has just enough room to get through).
Swinging more out to right field and the ball is now heading dead on target.