TD, unfortunately for you in your quest to find the truth you may end up using information from this RUMOUR forum when you have been at pains to present facts. A lot of people can post on this forum with varying degrees of knowledge and so comments can be varying from copperbottomed, to crew room chat to a Mate in the workshop told me variety. I beg you to consider all the information you use and get advice as to it's accuracy from someone who knows.
The comment at post 1249 made a comment on the ditching of XW666 and the BOI....
one of the points that came out of that BoI was a weight restriction to be placed on the back end crew as a result of a seat detaching from the floor on impact.....
may be a point you would wish to use to show that BOIs do not act on reccomendations.
I have a copy of this BOI, along with many other BOIs, in front of me.
Conclusions of the board, part2, para 56 contains the recommendations. There is no comment whatsoever on the placing of a weight restriction on the crew.
Part 56r does say that "The applicability, to military aircrew, of the airman weight factor used in current rear seat stress tests be determined." So not that crews should be lighter but that the weight used in seat stress tests should be looked at again. Probably ought to be raised as RAF rear crew are generally bigger now than in 1960s when the seat tests were initially carried out. A small point but if you were to quote incorrect statements in one part then they will use it to rubbish all your statements.
There may have been internal Sqn or other reports about rear crew weight and other instructions but it was not in the BOI so it is false to say a recommendation was not taken up.
As always I wish you the best in finding out the truth.