That and some green looking sludge between the glass and the silicone (?) strip seal that stops water dripping out when it's open (IYSWIM).
Any ideas how to remove?
It's a curved glass screen. I can't remove the screen or the rubber/silicone strip.
I have the following cleaning items: Mould killer, bleach, multi-surface cleaner, white vinegar, bicarbonate of soda, cream cleaner, window cleaner.
The shower gets used every day and SHOULD be wiped down, but that doesn't happen, hence the horrible marks.