What are the dimensions of the existing room without walls, where are the windows, in the toilet and over the vanity in the shower room? 3M x 3M what are we working with.

If you remove all the walls except the linen cupboard and does the linen cupboard also have hall access? If so get the linen opening out of the bathroom and have doors to hall side, which will make both elements work better.

I know toilets in main bathrooms are not everyone's cup of tea, but if you can have a 720 door from i take it, a hall, run a custom made vanity unit, and it must be custom made to fit exactly the space available, and take it from hall and over the toilet cistern, which should be a concealed cistern, maintenance panel is the flush plate, and just pan is displayed. Two vanities if needed, one bigger one is more on trend, and hang the cabinets off the floor under the vanity top, to make it look longer and makes cleaning under the cabinet so much easier.

That leaves a lot of space for the bath where the second vanity unit is now, which would look fantastic as a freestanding type.

A simple frameless glass or semi frameless glass shower screens, allow access to bath, so it might be say 1M wide, if you install those long grid type floor wastes and the shower is long enough you might get away without a shower door.

New taps nice big tiles to ceiling and this will look sweet. Close off the toilet and it becomes a bit of a rabbit warren. R

shower over baths are last resort if space is critical, but without any dimension we are all guessing

try to keep plumbing the same for less cost i would remove walls and create one larger open room .... too many doors is a mess ......i am designing at the moment and want one big room so movement is easier should anyone be in a wheelchair .....with 2 unmatched windows only one needs to be changed or create sameness with identical pelmets and sheers in same width though windows are different width or perhaps remove both if they are close and create one larger one

I know that having the toilet separated off from the rest of the bathroom isn't everyone's preference, but it's certainly what I grew up with in Canada so it's not totally off the wall. I guess my question would be, though, do you need that bath? If you don't, then move the vanity as you've already decided, and make yourself a nice big shower room. And, as the comment above suggests, open that linen closet up the other way.