Thanks for all the advice. I appreciate everyone's help.

Spoke to the guy on the phone today. Surprise surprise he said they would create the fall with the tiles and glue and that a level screed wasn't an issue.
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Employed a local Adelaide company who advertise as a bathroom company and builder....to do my bathroom Reno. They did the screed and some plumbing work and my 14 yr old…

I have had screed laid on the floor in my bathroom including the shower. My tiler has commented that there was no fall. We poured a bucket of water on…