Hi Neeno, I've seen the use of Zebra ( vision ) ROLLUP blinds with one for each side that will cover down to the lower half window rather than having four blinds and have them fitted to the outside top edge and to the side edges of the pelmets ( window frames.) (If you get to see utube video clips your see what I mean . ) The avantage of doing it that way will allow you to buy only two blinds rather than four . The cost difference between two blinds and extra fabric required to cover the two windows will most likely be cheaper than the extra cost of two extra roll tube mechanism / chains etc etc. when fitted in the recesses of the windows . Also ,due to the bulkeness of blinds , two would no doubt look better than four doing it the way I suggested . Fitting to the timber edges will offer a couple of advantages . One of which will clear the windout handles fitted to the opening widows . Two ,will offer better light reduction from night time lights as the blinds will cover right to frame edges. Three , the design of the Zebra blinds only requires a few inches of the chain movement to close up or open up for vision out or add privacy where normal blockout ROLLUP blinds needs more adjustments and will not offer the same privacy options that the Zebra blinds can offer . Also, if in bed you can open the Zebra blinds slightly by a few inches or roll up just above the top of the lower window ,depending on how much vision and privacy you need and look out of the window whilst still in bed. Being such narrow windows, the small bit of wall between them proberly would not mater if one blind fitted at the top came down over that wall area down to the bottom window. Also you should concider the solar film tinting to offer improved privacy and insulation & fade protection etc for when blinds or even curtains etc are opened up altogether . Although I'm in Tasmania , I have a manufacturer I deal with on the mainland that could arrange sale / installation if required using the Zebra blinds or other types as well contacts for window

@Wuff good to hear. We've settled on the stacker doors for those same reasons, for the project. Have bifolds at current house & I like them but at time of installation approx. 8 yrs ago we wanted them to fold inwards so we could screen them, oh no never heard of that, can't do that (they said). Of course now that's all possible, consequently rarely are they opened fully. At least we have a fixed/opening door on one side of the bifold set & also another single security screened door at the back of the house as a main entry point that we leave open all day.

Thanks once again oklouise for your comments. I have already been told by the draughtsman that I cannot put in skylights. No idea if this is true but he seemed quite sure and it was he who 'designed' the layout of said ensuite with what I consider a too small window because of ease of plumbing and drainage. He says that can be changed...............Supposedly only put like that to get the oversize plan in fir consent. This department is only interested in the outside view and the effect on the neighbours, which I actually dont have any. The positioning of the ensuite and WiR has changed too from the first plan as I had to come 'out' of my bedroom into a corridor past the WiR door and then into the ensuite. Technically they were both in my bedroom as had not entered the hallway but did not seem like it. So the wall you have now suggested for the door is a small lobby to the bedroom and I had planned to put furniture on it and a full length mirror. I will now look again at the whole space with three zones to see what can be done. I used the word solar tube as I thought that was the generic name for the 'tube' installed which reflected light into a room. Do they cause draughts? Have had no experience of them but will probably want to install one in my scullery (or Butler's kitchen) but am going to work in it a few months before deciding that. I am really quite a novice about function of installations and of building code.

Looking at the outside, why are the windows in the extension different from the other windows? Is it an aesthetic choice or a pragmatic one? Since the windows are different, why not make them a statement? Do something creative with the glass . There are all kinds of coloured and textured glass. Go talk to your local glassworks. Or investigate stained glass options. You can even paint glass with special paints for a stained glass look. You might be able to find a local glass artist who could design you something stunning. Look on it as an opportunity, not a problem to be fixed. And compare prices. You might find an option you can afford that turns the windows into a wonderful feature. However, if you really want a window covering, I would recommend shutters. We have recently put in plantation shutters in our back sun room. We love them. They changed the whole look of the room for the good, provide absolute control of light and privacy, and are much easier to clean than venetians. You can get them in any colour you want if you pick the right company and they are very cost effective in small areas, but be aware that they measure in place for accurate sizing and the actual shutters are custom made in China. Ours took over 3 months to arrive, due to Covid. Then we had to wait for the installer another week or so. But they were definitely worth the wait. They are hinged so you can open them out to easily clean the window glass, and the shutters themselves just wipe clean.