Completely agree with Jonathan. I have seen a couple of 70s houses modernised fantastically in my area, both with some type of grey/grey wood cladding in parts. It retains the 'character' (I'm sure in 50 years time this architecture will be to die for!) whilst giving it a modern twist. I also think the house is very 'garage heavy' so I would get a really modern garage door (possibly wooden) and try and have a balcony above to distract from it. See this fab example... [https://www.houzz.com/discussions/how-to-modernize-my-mid-century-split-level-house-exterior-dsvw-vd~3882230[(https://www.houzz.com/discussions/how-to-modernize-my-mid-century-split-level-house-exterior-dsvw-vd~3882230) This would only work if you extend fully over garage as Jonathan suggests, and would obviously require pp. Could be a fab master bedroom or upstairs living space if you did it though :)

I think I would go dark for the render like an anthracite which has a touch of blue in it and continue it for Windows, doors. I may be being totally ignorant (!) but would a glazier not be able to install mirrored glass cutting round the vent? If not, I like Jonathan's idea, there is a liquid mirror product on the market but no idea how effective it is or whether it would be suitable. You can also buy acrylic mirror sheets. i might also try removing the paint to see if they used the same bricks or not. If they did, you could add a window box as they have in the picture and you could add one of the window mirrors further along the wall (I really like Carolina's idea just not sure how it would work with the vent and position of the window next to the steps but may be wrong). I don't know if there is a cheap solution for the bricks under the top window. I would probably buy some tester pots in emulsion and add an exterior paint additive to make it waterproof or maybe find an evergreen climbing plant suitable for a pot and train it to go under the window

Said house!

Keep the bottom half as brickwork. Don’t make the mistake of making it too plain. My neighbour opposite me has a similar style house. When they purchased it they knocked off the render and beams and re-rendered it and left it white. No beams. It has modernised the look. I have timber windows. If you keep on top of the maintenance it’s easy. We have ours done every other year. A quick sand down and re-coated. Easy job for a decorator. Two days maximum work. Most of the houses in our road have UPVC windows. They don’t look as nice as timber. Two decided to have green which looks awful. Really doesn’t go with the style of house or the colour of the brickwork. If you do decide on timber windows personally I would steer away from Georgian design. That’s now dated. Nobody asks for them any longer, neither do they ask for leaded windows (i’m a partner in a joinery company and nobody ask for this any longer). I would also be tempted to keep the timber windows natural as opposed to painting them white. It’s far easier to maintain with a stain/sealant as opposed to sanding down old paint. Timber windows all the way for me. Just keep up to date on the maintenance and it’s not a long job.