Over many years of workshops and demos (and shoots too) my standard 4K OLPF has been bumped, prodded, poked by many lenses, lens adapters, greasy fingers as people played the camera. Sadly it's now it's starting to loose it's anti reflective coating so it needs to be replaced.
If anyone knows of a good one that's going spare please let me know. It's the vanilla 4K one that's factory ******ed that I'm after, not the 2K one (I have a nice one of those if anyone needs one).
Thanks. Fingers crossed, don't suppose it's a cheap spare part!