Good question as yes much of the stuff u see on Ali or eBay etc is not genuine 3M, or stored too hot and its useless, thus getting dumped cheap.
Also moulded pattern is not as grippy as cut-in pattern
In Australia, definitely Surf Sail Australia in West Leederville.
But its not that easy to do a neat job around handle, vent etc so i will mention that i can

Maybe tell us where u r located?
Mark
MOzCustoms
South Fremantle WA