Thanks guys - I've had a go at getting the best of both worlds.
I think the blue bias is a function of the unmodified DSLR's lack of H-alpha sensitivity and the CLS filter. I work with raw files and let pixinsight do the colour balance; I'm pretty comfortable with what it comes up with. The histograms look pretty well balanced to me, so I guess that's the data I got.
Higher res version at
http://www.astrobin.com/24986/
cheers,
Andrew.