Im lazy and bought them made from a guy on ebay uk called dave at rogue engineering.Nice quality and well made.He would have no prob posting to you.
A business over here called trafalgar services can supply them i found out recently.
http://wascb.org/?page_id=39
I thought there was a company in ChCh you guys used,Macallum i think or something like.Maybe worth a look for old posts from 7ish hes over your way and may be more usefull.