Wall not 90 degrees for shower tray

Sorry for the long post but I am trying to be clear...

I am trying to waterproof a shower I have inherited in my new house. I have removed the old sealant from between the shower tray and the tiles around two sides of the shower. I have discovered that the two walls are not 90 degrees to each other and that there is a significant gap (~ 1cm at its largest) between the tray and the wall caused by the off-square walls. The previous fitter has poured some kind of sand/cement mix down the gap and used a rubber triangle-section bead to fill the gap but I can't believe this is a suitable fix.

How would you normally deal with fitting showers in a space where the walls are not perpendicular to each other?

James

i should say something to reduce the gap and give it support so probably pour some kind of sand/cement mix down the gap and used a rubber triangle-section bead to fill the gap

its unusual to find 2 walls that are at 90 dgrees to each other

Yes, not unreasonable really. It's common to have to excavate a wall a cm or so to get the tray such that the tiles all land on the top surface where it's flat. The rubber quadrant stuff is OK but goes dirty eventually. It's quite easy to replace of course, or you can use a solid quadrant as is common in the DG industry. Wickes do one as well.
I like the quadrant because it means minimal silicone is showing.

Thanks guys. The shower has been leaking so I wondered if there was a better fix. I will try and reapply a new "quadrant" and re-seal. Perhaps it will be more water-tight.