Rosie.
Its the black wire that you want to splice.
Firstly, using a sharp knife or pick, remove all the crimped wires from their housings. Carefully bend the white pegs up and gently pull the wires out.
See how on the ego connector it goes black red black red?
Well we want to use the DM4 eyes with the order black white black red.
So we need to turn the single black wire into two black wires.
To splice the wire cut the end off a few centimeters from the crimp.
Now you need to solder two crimped ends on to the black wire, use the one you have just cut off, and another one from the ego eye loom.
Basicly twist all 3 wires together then solder as neatly as possible, then afterwards heatshrink the solder joint.
Now put the crimps from your '4 wire DM4 loom' into the 4 way housing from the ego eye wires.
I hope I have explained that clearly, if not I will do you a ghetto diagram in MS paint