To import he mocap data from mixamo.com into Houdini, I will need to use an import node.
I first used an agent node, used predominately for character model importing
It allows you to import the baked in motion cap data along side the model by defining mixamo as the source.
The model and the skeleton with animation are then imported into the scene.
Due to the issues I was having I discovered a better node to use for the import:
Fbx character import node. This can then be used along side a bone deform node, do define the bone transformations applied to animate the model.
Now I have imported the model into the scene, along side the animation.