Good day Shane.
It appears several different levers were used. By serial number you should be looking for M4284T lever (for serial number 140000 and above).
Below is a link to the parts catalog we can use online here in North America. I think you can access it. Part numbers may help in your searches, even for used parts. The versions of the 420 and 430 tractors are in the same parts catalog JD # PC505. As I mentioned in your other thread, send Lavoy a direct email (
postmaster@jdcrawlers.com) to see if he can help with a part.
PC505
You might want to put your general location in your profile, so it shows. Hopefully you find a source that will ship to you in NZ. A quick look on eBay using the part number brings up some, shipping will need to be checked in all cases.