Thanks Richard.
There were a few things that needed sorting out, the Image Map shaders need to Use UVs, but also they needed scaling, positioning and repeating, which is probably why it didn't work for you and I forgot to mention that in the post above.
I've attached a TGD with the node setup in the Object node so others can have a look, although they will need to plumb this into their own object texture shaders. I also switched off Ray Trace Objects in the render node to have a look at the displacement map and see how that works across the model (with it on, it treats displacement like a bump map which doesn't distort edges). I'd probably want to split the object into a third piece so that I could displace the main trunk more heavily than the mid sized branches.
The two images below show the AO effect on and off. It's an artistic thing on whether it works for you. I used a Colour adjust shader to lower the black level to -5 so that the blacks in the texture become 33% grey.
Warning tech babble....
By creating a range of white to black to be effectively 1.5 times what it was by using the Colour Adjust shader, the extra .5 is a third of the original colour range. So black level at -1 will turn the black to 50% grey etc.