Ah, sorry, I went deeper into the linked thread and saw the details about Tourism company responsibility. That does indeed suck. Hopefully they'll clarify soon if this applies to all foreign vehicles and motorbikes specifically, especially given how lax it was before it seems strange to impose such a large change now.

People on OverlandSphere fb group are looking into it with a view to getting changes made, but there seems to be no way around the current rules as they stand. Unless changes are made, transit through Thailand will be on the back of a truck and even then that is just a maybe.