It might potentially be better to order the 6 foot pound LGU
If they do the same with the LGU as they did with the LGV, the 6 foot pound version will have a longer latch rod so it will already be short stroked. Shorten the latch rod a touch, fit a metal 12 fpe UK spec trigger blade and a stronger spring - possibly look at lightening the piston and you could end up with a very sweet shooting LGU for less money.
Unless they've already thought of that for the 12fpe LGU of course. Assuming you prefer a short stroked fast action (I do)