Ouch that's nasty. You could take the lip off and just epoxy glue it on the mating surfaces of the crack. You'll get a seam in any case but if you keep the lip covered with plastic conditioner or something to give it a glossier finish it may not be as noticeable.
I cracked my Ultrex lip a few times but it was in the underside where it mounts onto the bumper. Mine is held onto the bumper in various places now by metal fold-back clips (from Officeworks)

. It actually sits flusher and more tightly to the bumper than with the original clips and screws, which allowed it to sag in various places.