tbh, this is one of those things where you can't really go cheap.
you see that whole black housing on the rear of the headlight, that holds all the gubbins, that's the important bit.
I beleive that is where most of the optics are calibrated and determine where the beam is aimed.
If you had both gubbins from the UK lights, then I suppose you could buy US lights, take them apart and combine the US front half with the UK back half.
I dunno, just thinking out loud with my gorilla brain.
PM P15ULT perhaps or Husky and ask, since they seem to have most experience with headlight modding