The Bivi is Top Fabric: 20D Nylon Ripstop WPB, DWR/10,400MM PeU, 18,300 g/day MVTR, Bottom Fabric: 30D Nylon Ripstop, DWR/1200mm PeU, FR CPAI84. In fairness I am reconsidering my initial thoughts as I remembered that I left the top fully open and tucked it inside the bivi this there was double fabric on the upper face. I will give it another go later in the month and give it a chance to breath next time. A smash proof bivi would eventually be the way ahead.
I did get a reply from Carol and he was very helpful. I need to put the tent up and use a hose to see how the inner doors got wet. It only happened at the end of the trip but just need to check if it came in a seam. Carol stated that this has only happened once before and is keen to check if this is a problem. I think also I may have made the wrong decision in getting the S22 over the S20 as I only need 1 entrance. But it will serve as a 2 man going forward. Longer trips I will revert back to my S15.