I am reporting back having experimented a little more and I think Pete-zza has cracked my problem - I think it was the incorrect activation of the ADY. I tried using 0.5% IDY today mixed into the dry flour (I used 75% Type 55 French flour, 25% regular bread) with 66% lukewarm water and 2% salt. It underwent a 16 hour cold rise then 1.5 hour countertop (I was being impatient!)
The difference was huge - previously when I take my dough with hte incorrectly activated ADY out of the fridge, it is very wet and ulta extensible to the point of being unworkable. It is also usually also very gummy. This time the dough despite being a little wetter than usual, was very dry and easily came out the container onto the bench (usually it is a struggle taking it out). The dough was also much easier to work with - I could shape it much more easily than usual. The pie cooked in just under 2 minutes.
There was much more cornice rise than usual with bigger bubbles, although there were not huge bubbles all the way round, there were certainly a few areas with nice big voids. The people who ate it also commented on the additional airiness.
I have attatched a picture, and I am much more happy with my results now, so I would like to say thanks to everyone, especially Pete-zza, and my next experiment will be with a 24 hour room temp rise. I would also suggest people try sourcing some Type 55 French flour as it is very tasty!