In a shower that size you don’t have room for a sliding door. Why change the toilet position?? A great deal of money required for really no change.

Shower base is fine I have them. Get a low profile one.

@dreamer only because right now it's a bit of a squeeze and if I lean forward I hit my head on the shower screen. Not really a big issue, more so that when my daughter uses it and asked me to wipe her bum she often knocks her head on the screen. We need to gut the bathroom anyway due to water leak problems, you see. And the downstairs ceiling is currently exposed because we are renovating downstairs. Builder said now is a good opportunity to reconfigure the space if we want

Swing the vanity to be on the bedroom wall next to door. Go a narrower model if needed. Keep the toilet facing the way in your new design but move closer to the window. See if you can increase the shower size from 900x900 to 900x1200 and as above use a low profile shower base.

Thanks @bigreader . You can't see in my above photos but the door is next to the shower.

Re: position of the vanity, did you mean this?

If the bathroom wall with door is 2330mm, then you have wall space, as per Bigreaders suggestion to have a 1200mm shower recess.
Thank you for the extra information. It’s handy to have all relevant information when answering your query.

Yes vanity opposite toilet to allow for the bigger shower.

That’s it Kate :)