Wow thanks for that Keppel never actually thought of using a texture map. Which by rights should keep the colours accurate if the emission strength is ramped up which it didn't do using the colour ramp as the blue and red looked like they mixed with white. The scene I'm using them in has 12 of them all different colours at each end but doing gradient maps in ps wouldn't be an issue at all if the end result is as you showed.

(ps really need to do my test renders in a box shows the lighting in a much better way :) )

Incantrix