The Ledbury tile although smooth, has a micro-texture that gives it slip resistance. Downside is that the packing wax gets a good grip of it. Another thing that doesn't help is that sometimes during manufacure and packaging, the wax is applied before the tiles have sufficiently cooled, baking it onto the surface making it an arse to remove.
The wax used is silicone based so the best solution to remove the bulk is a scraper, as you have done. But it can still leave a residue. We've found that if you use a silicone based aerosol sealer, like Sealguard or the LTP Grout & Tile Protector, the silicone in that will re-activate the wax to some extent. So spray, scrub with a white or black emulsifying pad, and wipe clean with a microfibre cloth. Should be gone.
The first time i tested it was at a customers house. Much worse than the Ledbury tile, but scraped and cleaned 25 sqm in about an hour n'arf.
Factory won't do anything about it as they say the tile isn't faulty, but..... Time is still money.
Its something the customer should be able to do. Happy to supply all the stuff they need FOC. Did you buy the tiles or your customer?