Its good to see so many responses. Thanks.
I'm using a gas deck oven with a 3/4" marble slab. The temperature I'm finding works best is 310C (590F)for the top heater and 240C (464F) for the bottom. I'm using a non braomated flour with 14% protein and 62% absorption which I'm assured is ground very fine though I can't tell by the feel. I think my supplier told me that they run it twice through the mill.
I'm not the most computer savy person on the planet -what's wrong with an abacus?

- but I will try to get some pictures up soon.
I increased the flour yesterday to bring the hydration down to about 67% as the undermixed dough is easier to work with but not when it becomes a puddle in my dough tray!
Yesterday's mix:
Flour 2050g
Water 1350g
Wild yeast preferment 500g (83% hydration 227g water, 273g flour)
Salt 35g
EVOO 25g
Nice to see you Tom. This is one of the main things I'm playing around with at the momment. It seems that the dough works better if I let the yeast get a bit of a start before putting it in the fridge.
In order to get the preferment near peak activity when I come to use it, I do several things. I make a thicker preferment (83% rather that 100%) which should slow the fermentation down a bit. I keep it in the fridge during the day and feed it last thing a night (about 8pm) when it sits on the counter 'till morning which is when I use it. When I arrive in the morning I mix the preferment with the water and a handfull of flour and let it sit for about an hour in order to "wake up" before I start making the dough proper. The preferment has more than doubled in size overnight and there is no apparent colapse of the bubbles on top although I suspect that after 14 hours it is past its peak.
I then autoyse 2/3 of the flour for 20 mins. Yesterday I mixed for 6 mins. Rest for 40 mins. Take it out of the mixer and rest for 10 mins. Ball and straight into the fridge.
The dough is about the same as the ambient temperature after mixing (80F). It is very wet so I don't think the mixing process warms it up much at all. I have tried using refridgerated water but it didn't seem to make any difference.
After a night in the fridge there is miniscule extra rise. However even straight out of the fridge into the oven I get fairly good oven spring. If I let the dough warm up it will double its volume after about 3-4 hours which is great but it has to be treated with kid gloves as it is very floppy and fragile at that stage.
Thanks again for your time guys.