Ha ha, it is a preferred operational requirmenet, but nothing is stipulated that that is how it will be (as far as I am aware). Ultimately it will be wind dependant but the published op procedures state what I said above.
Minor point but the runway is north / south not east / west (sorry, just like to be precise from time to time). The departure routes do turn either east west depending to avoid bawtry anyway ... this has already been thought of!
I'm not operationally minded, and it's not my forte, but i'm into all that ... and I do have an idead of the thought processes involved and seen all the bits and pieces!
Going back to the displacement issue, the runway is not shorter, and it is quite common for runways to have a displaced threshold, runway 09 at LPL is displaced by around 150' as is 24R and 24L at MAN.
GJK