In the end, I just created a simpler workflow using Apulsoft SplitS, Sonnox Soften etc and its magic; by far the best outcome over 40 years of mixing so, whilst Silk caused me to dive deeper, Im still happy
In the end it was Silk but rather RComp which was fed the esses and choked on compressing it. Ive used it for decades but time to move on 
Thanks again for your replies and concern…greatly appreciated Simon