From what your describing we had the same thing going on,I didn't like the ensuite( too small) and the bathroom needed to be bigger,so we got rid of the ensuite and put a door between our bedroom and bathroom like a jack and Jill.After a while I felt it just didn't work so we closed up the wall and we now have one big bathroom.im glad we did it now. I too wondered if it would devalue the house and I'm sure if a larger family moved in it could be a bit of a problem,maybe someone from the real estate world will pop in and give you some advice. Good luck with whatever way you choose to go.

Update -- my plumber finally returned. Not sure what he did while here, but he told me again it wasn't working -- then he did some work on a radiator which had a small leak. We were having a long discussion about options on pumps, new showers, taps etc and I read out the installation guide and he tried it again, and suddenly it worked. It is bizarre as I don't know how many times i tried it previously. My friend who works in construction ALSO called earlier today and tried it several times to no avail. It must have been extremely stiff or perhaps the plumber realised some airlock whilst fixing the radiator since I think water pressure is much stronger since he went. Thanks for everyones help -- i learned lots on plumbing and a valuable lesson to take out the installation manuals myself and not trust that trades men know everything!!! I feel like celebrating!!

Front hallway- I say save your money leave it up. Cost of removal is minor but you will likely have to move radiators and electrics and make good plasterwork and coving- I say protect another £1500 profit. Present the larger back reception as a living room and present the front reception as the dining room. Given that the bathroom is likely to go upstairs make the downstairs bathroom into a room to access the garden- I would present the kitchen as a kitchen/breakfast room with doors to see the garden as being able to see from the front door to the back garden should pay dividend.

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).