Thank you both for your replies!
James - yes well, we are total beginners, experimenting and learning as we read / try things out and talk to other local organic farmers. we have been trying various methods of making our own compost - all going well, but very slowly so we are yet to use any of it on the garden. we also have a compost toilet just recently made up - so we will eventually be composting all over the place!
we have tried out the grey water system as we wrote out above and so far so good - the water comes out clean, it takes time to filter through the layers - which for some reason gives me extra piece of mind..,
We are using our own home made potassium based soap - our soil could do with more KOH and we defiantly do not need anymore sodium - which is in most eco soaps and already in high amounts in our tap water
Tyler - yes we did have a look at this page and I too am worried about using the grey water in drip irrigation, but I am hopeful that if we keep a good eye on our system (everything is very accessible and removable) we can avoid overly dirty grey water from getting into the pipes maybe.. we are thinking of adding a second bin to the system which will have a second round of filtrating before the water goes through the drip irrigation system. I can't think of any other system that would allow us to re-use the water without spraying over the veggies, any ideas?? The sun here is so hot that water when sprinkled from above doesn't really reach the roots much..
Another thing to mention - we were also thinking of running extra tap water through the system so that the tap water comes through a little better quality for the plants, as the grey water won't be enough to feed all plant's this can also flush through to top them up a bit..
We need a lot of water to water all our veggies and it barley ever rains here ;( - so grey water has no chance of sitting around for more than a few hours as it will be used on the same day