I sent the first Hairball back for testing/repair late last week. Later that same day I did a test drive around the block and the Zilla tripped out again with the new Hairball, and I had to get it towed home again (fortunately only a short distance this time)

Since then, the same old error has been consistently reoccurring. I don't know why the new Hairball worked for a couple of KMs then stopped - possibly just coincidence, or possibly something in my setup is murdering Hairballs. (Proximity to the power box? It shouldn't be something that can cause damage, but you never know..)
After further discussion with a guy at Manzanita, they've asked me to send the power box back for testing. This is pretty bad news, because (a) I have to take the front battery box out to access/remove the Zilla and (b) round trip postage of a 15kg Z2K will be hundreds of dollars. (Since it's out of warranty I'll probably open the box up myself and do a cursory inspection for loose wires / visible damage first.)
Oh, and yesterday I received the NCOP14 approval from the DoT, telling me I can bring the car in for pit inspection and licensing. Which is a little bittersweet as I begin to disassemble the car again to get the faulty Zilla out!
The trials and tribulations of building EVs.. *sigh*