unless you have a very big bathroom the actual laying of the tiles could be the smallest cost of the whole renovation (what is the size of the space?)...there's also the removal of the old finish (and any old asbestos) and preparation of the new surfaces and waterproofing and any new fixtures and tile glue and trims and grout...ask the tiler what is included for the price

there is also a difference between ceramic and porcelain tiles - often these issues come down to a combination of (a) tile batch size/consistency (b) tiler's skill/capacity (c) communication in that if the tiler opens the tile box and he can't practically achieve what he thought he might because of the general discrepancies in size then they should at least speak to you before they start. So often with many issues in this game, it's about managing people's expectations and having open/honest discussions at the right time. When this breaks down, problems and disappointment is more likely to occur......so coming back to it, if you have high quality porcelain tiles that are millimetre perfect, square and flat then the capacity to lay them with minimal spacing is higher. Also the substrate/prep plays a part as if it's all out of whack and not perfectly straight/plumb/square then you'll be in all sorts trying to achieve the minimal tolerance detail.

No idea in terms of pricing company vs company. All brands we’ve looked at so far have had three or four tiers with their pricing. So each product falls into a category eg. Essentials (cheapest), Premium (dearer), Luxury (dearer again) and Exclusive (most expensive). I wouldn’t limit yourself to a particular company, I’d be looking at the ones you like best and seeing what category they fall in. Have several options so you can get several quotes.

Why have you quoted all sizes in feet and inches. We have been using metric in Victoria and Australia since 1974.