Right, you can get all your rod building stuff direct from Mudhole in the US. They will ship direct and its not too bad, but if you are only getting bits and bobs, then Guides n blanks or David Norwich. Jakes Custom Rods down south also do Flexcoat and FC Lite.
As for colour preserver, if you are using thread that is not NCP, then I can only recommend the Flexcoat Color preserver and thread sealer at about a fiver a bottle as its the only stuff I use.
Gudebroad NCP thread does not need a preserver and has a bit of a sparkle about it in sunlight. They do an orange, but its not "neon". The alternative, and you will need to get from the states, is ProWrap colorfast thread code 225. This is proper neon orange and its the stuff I use on beach caster tips, but I have only has size D. Fish hawk threads also do, again from the US.
However, any orange thread will dull down if whipped over black. With the beach casters, is we want the really bright colours we whip an under whipping or white or silver and then the colour over the top. Not an option for you I guess. What I did on the tips is paint the blank white with a spray paint. I then whip over it with the orange. This will make it keep its "OUCH" factor. If you use a reflective white paint, it is even better.
Are you doing the orange so you can see it better on video for analysing the casting? Might also consider using reflective tape/paint as this shows up really well on footage if a light behind the camera is used.
Hope that helps