I’ve done a bit of reading, I see that there’s not enough leverage to remove the freewheel when unbuilt. However, the good news is that the flange is high enough and the sprocket small enough that the wheel can still be laced without removing the cassette.
A buyer could lace it with ‘z’ spokes to get around the freewheel still being there :)
http://www.wheelfanatyk.com/blog/z-spokes/