I've bought the uni-mould kit (and resin infusion kit) from EC as I'm wanting to make a mould of a racing car nose cone.  There are a few features that make it a little more complicated so I'm a little unsure.

My thoughts are to have one piece as the very front of the nose coming back behind the fins and then the rest as two further pieces

Are there any split lines visible in the original part?

Yep the flanges. You will need a good 2-3 inches. 

Just looked at the other photos. Are you Andy from Bristol? 

yeah ive been speaking to andy on email, still need to get along to a bristol mc club meet.
But with regards to the mould, you will always make your tool bigger especially with going down the infusion route, I see you have a return flange I presume so it can attach to the front bulkhead. I think you are on the right lines with a split down the middle, Im not sure how the wing pylons would release as i cant tell the undercut from the photos. But a simple return flange on the rear mounting should be easy enough to add.
How does it attach to the car? Is it zsus fasteners?

Ah!  I've just put two and two together and worked out who you are.