Your 2mins beat my 14mins, and i was rendering on i7-2600K with 8gb Ram. Why such a big difference?
That wont be my final back plate, it was just an hdri i am using for the time being but was thinking of removing it and using maya sun and sky. So when it comes to final comp i will be using a different image.

I am also using cm as my current unit scale, so it is at scale (50cm=500m). Would it be better to create it in meters so the scale is 1:1?

As you can probably tell i have never made a scene like this before, but i have learnt a lot so far, so thanks for your continuing help