OK, so after a bit of a long-winded phone conversation with the missus, Noarng agreed to fix the issues.
Step one: re-siting the water feed pipe and waste pipes for hand basins to a higher position so that the pipes can be hidden behind ceramic mounting unit (as intended) and not hang down below like a bunch of blue pudenda!
A= original height, B= new correct height.
A would have been fine if the sink units had a floor standing pedestal, but we couldn't find one that matched and fitted the sink shapes we liked, so went for wall mounted instead, so this is what caused the issues.
We did however choose the bathroom stuff at the same time as the tiles (Noarng was actually with us during this shopping trip), so really the measurements for installation should have been cross-checked against the plumbing on site at that time BEFORE tiling happened.
Step 2 is re-positioning shower unit to sit 90 degrees to wall with shower head mounted, this hiding wiring and no need for stick-on uncle bob's DIY surface- plastic conduit...which means also that a longer water feed pipe needs to be purchased (and I can't help but think this was also a constituent factor in the decision to mount the unit where it was!).
Not sure what is going to be done about the plastic dicombobulation that carries the power to the over-mirror light in the master bathroom.. might as well re-position that too, it's only about 5 inches, but will still mean some chasing, a short length of conduit (hopefully) and a new tile being placed with a hole cut.
Also purchased a 2000 litre green plastic water tank directly from the manufacturer (which just happens to be the nearest source and also saved us some beer tokens!)
Getting there.. slowly!