Seemless floor in for shower polished concrete waterproofing?

Hi

we have just gutted an old bathroom and spare room. Both will become one big bathroom 5.4 x 3.7 m is the entire space.

the old bathroom had a 930 x 930 shower pan that was cut approx 50mm into the slab the house sits on (single level double brick home).

The perfect outcome for us would be to fill the old shower pan cavity with concrete, grind and polish the floor to have all one level.

the bathroom had the traditional mud screed 40mm thick with tiles laid, all this has been removed back to the original slab (hard going getting all that screed mix out after it's been there for 25 years)

ive vey spoken to a few concrete polishers about using the original slab as the shower base as well but either they have no knowledge in the waterproofing areana or they don't want to know about it.

1 guy said it can be done they have heard of it being done but had no other details.


What tradie should I be seeking for this? A floor guy, a bathroom guy or a waterproofing guy?

Has anyone seen or had experiance in what I'm trying to achieve if so please can u share your knowledge with me?

I would like like to extend the shower area from 930x 930 to 1400 x 930 mm (approx) and at the same time avoid cutting into the slab.

We have considered using an epoxy flooring but this option is not the desired result we would ideally like.

Happy to to provide more info and photos if there is not sufficient explination above.

Thanks
Brad