Vectis shower screen

You can lever the shower screen out carefully with the use of a wide, flat bladed screwdriver placed above the top edge of the screen

You can use any of the proprietary products for removing coffee tannins from the shower screen and then it should be ready to re-use. If the shower plate is fouled with silicone grease you will need to use acetone, citrus solvent, or brake cleaner to strip the grease away first