Thanks for all your comments. I have gone with an unfinished edge like Rukmini's pictures (sorry Sonia :D) as I think it will just look a bit more interesting especially against a dark navy wall. I have tiled around the window but not into the window recess. I'm pleased with how it looks so far - will try to remember to post a pic of the finished room!

I would get advice from a builder or a structural engineer before you go any further. I would imagine they were 2 rooms previously and someone has opened it out, but the main question is, is the wall a supporting wall? If so then a lintel (steel) should have been installed to secure the building above it.

I totally understand your pain - we had a saniflo a few years ago and they are notorious for going wrong and being noisy. They're not great to live with. My guess is the en suite and saniflo were installed by a previous owner so that this flat could be inhabited more easily by two "young professional" renters, as opposed to a family who would probably be happier to share a bathroom. So the first thing to consider is your circumstances - are you happy to share a bathroom with the occupier of the other bedroom (you've said it's a spare room for now but might you want to rent it out at any stage)? And the second thing to consider is whether you feel you're happy to lose the potential value in having a second bathroom - ie how long do you intend to live in this flat. If you might move on relatively soon, it would possibly make more sense to keep the en suite because you'll be more focused on short term returns on your investment. If you think you'll be there for several years, you'll be more focused on the livability of the property and making it work for your personal circumstances. Well I would be anyway :) If you're in that second category, it might make sense just to get rid of the en suite and either take down the walls to make the bedroom bigger (an office nook, perhaps, which still makes use of the light in the room as no wall between), or use the space as a walk-in closet. Good storage is a lovely luxury and you might find that more useful than the en suite.

Hey guys, I'm building a stud wall behind my garage door (metal door) to use as a recording space and I'm wondering about the best materials to use to create a good sound barrier with good thermal performance too. I was thinking about using 4x2 to make the frame and on the side facing the garage door cover it with some high density material. I'm not sure if that could be OSB as it seems to be more resistant to humidity as well. Inside the wall I'm planning to add 90mm PIR insulation, and then on the inside 1 layer 15mm acoustic plasterboard with a layer of tecsound and then another 15mm layer pf acoustic plasterboard. I'f anyone has any other suggestions about different materials I could use it would be great.