Thanks John!
I was actually quite pleased with how easy it is to bring the FormZ model into TM. I exported the model in parts to make it easier when there were design changes. For example, I had layer groups in Fz for each building, the site, street lighting etc. So when I had to make a change to a building I just exported it to overwrite the asset and refreshed the import which means the rest of the model stays as it was in TM.
Also I had used Maxwell for the stills but when I needed to go to TM I obviously had to place the trees again so I created a layer in Fz with small cubes where the trees were (Maxwell mxs references) and exported that into TM. Then I could place the trees in their proper places and turn off the tree placement cubes later.
Here are a couple of the Maxwell stills..