Is this a bedroom? I would not do blackout windows coverings any where else I would also need some idea of the space and what you will use it for and if privacy is an issue and of course your styleIf it was my space I would do solar shades to control heat and UV rays they would let me keep the view and I actually don’t care if someone sees into my LR but of course my bedroom would need drapes .

Sliding panels might work. Varying degrees of light control. Can hang from track in ceiling.

Here is one example. Not sure what’s available in UK. These come in many colors, patterns and sizes. Hope this gives you fresh idea.

I’ve not considered those, thank you! Not sure if it would work with the angled top side of the windows, though.