Thanks to Rick, Lance and Martin for your very kind comments.
Rick, I have added the markings to the front of the aircraft but the roundels are translucent showing the wood colour through and then a distinct line with the white. I cut and added another circle of white decal paper and placed it over the roundel but there is still a slight difference between the wood and the white showing through. If I had known that this decal was so translucent I would have applied a solid white circle first then the decal, we live and learn.
Des.