Thanks for the replies. I did find it in Sup. procedures I had missed it first time around.
FCS, I asked the question, I would hardly have asked if I already knew the answer. I did my type rating in CAE which as you may or may not know is a large, multinational provider of ratings for many airlines. I also passed the tech exams and flight tests as laid out and approved by two national authorities. We could go into another debate on minimum cost minimum standards style of civilian training but I think it's been done already? Thanks for your contribution, if it's made you feel superior I'm glad to have helped.
I had never been made aware of this option, and as it had never been demonstrated to me or had I ever even seen the defuel valve before, I thought it best not to dive headfirst in to a technical procedure that I am not proficient at, a 25min turnaround is not the time to start experimenting. The Captain incidentally has over 25,000hrs on mostly Boeing types and also was in the dark about this.