I'm all for dropping the "trials" from the title. I get the thought the term was used to allow a quantity of a different rifle be produced without being accepted first. Sort of a heading to put on a production order...
For a bit more study on the MkV, there has been a survey of serial numbers and some descriptions run by "ansleyj" over at gunboards, link below... The info is a bit fractured in format due to the board upgrade a while back.
POLL: SMLE V survivors
As for their fate, wasn't it rumoured the majority of the MkV's were given to South Africa in the thirties? I seem to remember something about this, or was it another myth that should be on my "Gems" thread.