How do I bathroom / kitchen / extension? etc.

Where we gonna put the TP holder!?

side of the basin? in a fancy recessed cubby built into the side of the tub? (likely crap ergonomics as too low). Disappointing you haven't stuck the loo opposite the doorway for those door-open eye–contact dominance shits.*

Why is the tub not flush with the shower end? or is the tiled recess for classy sit-down showers?

Have you considered moving the taps further towards the towel-rail end so you can set shower temp without having to get into the tub/behind the screen?

I'd be tempted to put a cabinet under the basin for extra storage – when I did ours we had a recessed cupboard above the cistern (toilet roll, a few towels (rolled up, held in place vertically by a lovely brass rod), bath toiletries), recessed cab above the basin (daily stuff) and two drawers underneath (can't even remember what went into there) and once idiot child #1 came along we hit capacity disappointingly quickly. If you can live with the one cupboard I envy your monastic lifestyle.

^{*(we have this, I hate it. With the door open I can see both through the landing window across to next door AND down the stairs through to our front door.)}