So on reflection, the idea of having the ice men on top of a snowy hill doesn't work. The hill would also need to melt and I then miss out on the shots of the dripping ice men onto the ground.
So I've decided to place a model tree, into the silver cloud time lapse footage...
And! Have managed to model this tree - sooooo simple, using cylinders, lattice deformers and duplicates of the same branch...all snapped onto the main tree trunk with the 'make object live' command...
Now to UV map it and make sure the resolution is the same for all the branches....