[Weasel]

Thanks for all the replies, I appreciate it. So the only practical solution was to start over again (I tried just deleting the Chinese from the purchase menu but phantom entrenchments were left on the map even after hitting the 'dig in' without units). I can dig in the USMC and that is fine, as long as I don't dig in the Chinese (attacker) then they will be without trenches.

One thing this map needs, which SP doesn't have, is low bushes/scrub. The Chosin hills are mostly 3 or 4 foot shrubs and undergrowth but the closest in the map editor is tall grass.