I believe you call them Lori's over there but the repair shops that install and replace 🚛 trailer tarps would be a place to check out. I buy the used ones off dump trailers for covering hay bales for $20 a piece and most of the time they are in quite good condition yet. When im lucky I get ones that were used for grain trailers, they are much more particular and replace them much sooner than gravel and coal haulers do. They can also customize the used ones usually to your size and tie down requirements not going to be cheap but will definitely last they're like a rubberized canvas here in the states.