Firstly, I do not work for the company but I had to tell someone about how clean my shower room is now that I have used this [smie]. It's flippin' brilliant (cleaned all grouting and silicone seals completely) and saved my elbows and wanted to pass it on!
<<disclaimer, it REALLY stinks so make sure you open all windows and doors>>
I've been using that for years and it does work. It only smells of bleach really - which is presumably what it is. [shrugs] In fact, perhaps plain bleach would work just as well and cost a fraction of the price.
Can't believe I've only just discovered it, tbh it probably is just bleach but bleach of such intensity that I've never seen before. I tried everything in my shower room but this is the only thing that has worked.