I think that the following post by Hartley made on the Bamber forum is excellent and well worth adding here.
Anyway, again as you know very well, exhibit references include the initials of the person who discovered the exhibit. It was mistakenly identified as SBJ/1 in reference to 'Stanley Brian Jones'. This error was then corrected as Jones did not discover the exhibit, David Boutflour did, so the reference DB/1 was applied. It was later discovered that there would be a clash of references as the police officer David Bird had already used 'DB' to signify exhibits discovered or produced by him. So it was eventually decided that they would use 'DRB' for David Boutflours exhibits with the 'R' representing his middle name Robert.
That is the reasoning behind the changes in exhibit reference given by the police, it is documented very well in witness statements taken around 1991 as part of the COLP investigation.
That is not my opinion, it is simply the official chain of events given by the police and is well documented.
If you want to challenge that official chain of events then please go ahead, but I'm sure you do not require my input to do so.
Thank you for the attention though.