Hi Ron,
I was just whiling away my lunchhour when i stumbled across your enquiry about HMY Mollusc. I am not sure whether it has any bearing on what you are looking for, but my grandfather was the gun layer on Mollusc when she was sunk. My grandfather is sadly no longer with us, but I know that my Aunt has photos taken on board and there used to be a nice framed photo of Mollusc on the wall, with the other ships my granfather served in, which I am sure must be about somewhere! My Grandfather said that nobody was even injured when the Mollusc was sunk and that he regretted not going back for his best suit!
I have also read on a diving website that the Mollusc is a popular wreck to dive on, as she is in relatively shallow water just outside the entrance to the Tyne. Give me a call on 01895 451977 (office hours) if you want any more info.
All the best, Ian