Thanks chaps.
I've now finished the tube more or less. Just needs some texturing work to complete it. I'm not totally happy with the lighting, but it turns out there are differences in how the tunnel was lit in the mini series and second season, so I went for a compromise between the two.
I made a quick vid showing a pilot's eye view of a launch. Might have a go at a more extended video once I've completed all the bay.. oh and a Viper.
http://www.johnpearse.partsking.net/tube2.mov