So we now have an 'underwater' ceiling.
We lined the ceiling with reflective foil insulation. The internal temperature today was .4 degrees warmer than outside. Much better than 5-6 degrees.
I also put the shade cloth back up along the back wall to reduce the glare.
The next issue to be addressed is to increase ventilation. Will replace 2 of the glass panels with some prop-out timber panels, (with must-have flyscreens to keep the creepy-critters out)
Should be muchbetterer