Hi All - taking on board your comments I have come up with three variations. Of course would love your comments! The distance from vanity to WC in plan 1 is approx 60cm - it could be made a bit more. This falls within the guideline you posted (23inches). More space could be created by making the shower a bit narrower (shown on all 3 plans as 1m wide (39 inches). I don't think there is quite enough space to divide the room and the problem with the idea of the bath right in the middle is that on a practical basis we would have to walk around it on a daily basis to get to the shower! Could quickly get very annoying!

Both Hansgrohe and (Friedrich) Grohe are German companies; Friedrich was a son of Hans who went on his own in the 1930s, so they share a certain heritage. These days, Grohe is larger and no longer family owned. Both produce outside Germany as well as on their original German sites still. Both produce "basic" and "high-end" ranges. They're both regarded well back home in Germany, much of the choice is down to personal preference. Hansgrohe is on average slightly more expensive (but not on everything). They also own the Axor design brand which has a more "ecletic" selection. One can mix-and-match; in our bath (bit messy, sorry - we're using it for the washing up while waiting for the kitchen to be installed), the mixer is Grohe as is the shower wall outlet, the shower rail and head shower arm (just above the shower screen) are Hansgrohe pieces. At least the chromed finishes are very close for the two: Both can be sourced well below retail list prices - if you're prepared to wait, German online sellers for bathroom goods tend to have many-months delivery timelines. For Grohe essentials (the classical Grotherm mixers) at least, any German DIY shop stocks these at very attractive prices (the difference to the UK retail price list will pay for the ferry ticket and fuel).

Type of shower depends on your hot water system, https://www.plumbworld.co.uk/blog/what-are-the-different-types-of-shower

I would move the basin back to the wall opposite the wc. The benefit being you won’t be stood under a beam, it’s a wider space allowing a better mirror and storage. Plus it frees up some wall space near the shower for a towel rail.