Thank you Martin,
I've been playing around with this modded 350d since I got it a few months ago. Although most Canons " sweet spot " for SNR is iso800, this particular camera copes much better at 400. The other thing I gain massively between 800 and 400 is dynamic range. This is something that again I have had so many frustrating hours to find out. Yes it means more data is required, hence why I was so annoyed that I lost an hour in this set because of a gutter. But as far as the cameras setting go, I think I've finally found what this camera likes. Now I can start bumping up the sub lengths again and find what works best.
As far as Startools goes, I'm just going to come out and say it, I don't like it

...... I honestly can't tell you why, I just don't. PixInsight on the other hand I think is awesome. And at some point, I will head in that direction.
Thank you for you input Martin