Limescale is a pest, but a mixture of two parts salts of lemon to three parts washing-up liquid of whatever brand you use, dissolved in a kettleful boiling water, then the bucket topped up with cold water, works well on bathroom tiles and basins, and on glass, although the toilet bowl may need to be left to steep for a couple of hours ,or so.
Use the upstairs one when cleaning the downstairs one, and vice versa, or the garden!
I would be very cautious about using this mixture on perspex or any form of plastic. I have no idea if it damages these surfaces, but I suspect it does.
A glass sided shower cabinet is the sort of thing that should be dried every time it has been used. Good luck getting the rest of the household to do so! This is really best with tiles too, but none of us bother, do we?
Depending on how hard your water is and how often and for how long you shower, you may need to clean it weekly or once a month if the job is not to be too arduous.
The mixture I recommend must NEVER be used on marble or terasso, as it most certainly will damage these surfaces.
