Blimey I’m glad I asked! So to be clear, I’m fixing this to the porcelain tile (rather than the glass) which has a smooth matte finish.
The command strip things look good but the website only says suitable for damp and humid conditions. I think my shower cubicle can be described as wet so not sure that’ll work.
Sugru looks like a good shout and it was their wee videos that keep coming up on Facebook that made me think about sticking rather than drilling. It is silicon based tho so might have the same vulnerabilities stated above?
With the polysulphide, can anyone recommend a profuct? Googling took me down a rabbit warren of polymers, modified polymers and modified silane products. Something I can pick up from screwfix or tool station would be ideal!