Nick, you might wanna have a look around PRANBURI HUA HIN thailand maybe, i m not too sure but Will and i met a nice chap during the 2018 oceania :/asia under 17 olympic qualifiers TT racing for argentina, i think this person was producing or sort of shaping those kinds of boards there...cause some of the TT riders were using that board for sure.
don t really know if he still does actually, but he might have a few left in his shed, if you manage to get his contact , i m pretty sure he WILL HELP you cause he s a real nice guy, he gave Will a sort of light trouser wet suit to avoid beiing stung by jellyfish, after a few ttipers got stung bad.
hope it helps...