We have a similar problem in that we really don't like our brickwork in our 1980 built home and have the dark brown window frames. Some people just can't understand why we dislike the bricks and I thought they may grow on me. After 4 years I still can't stand them and can't wait until we can afford to render. If we had a small area like yours I would have got it done long ago. Ours is huge. Don't be tempted to bag the walls. I've seen some shockers, usually people trying to do a cheap 'flip'. As for the windows, my uncle who is a painter & decorator said that as long as the frames are cleaned well they are OK to paint conventionally. The channels will be tricky, but ours need new felts etc. anyway.

guess you would have completed the update by now but just in case, They built great houses in the 70"s, a lot had concrete tiled roofs, have them checked and if sound paint them grey along with gutter and barge boards as you suggested but please do a soft grey otherwise it will look too top heavy, down pipes same colour as bricks (photo of soft grey roof) Paint garage doors same as brick colour minus the stripe, Front entrance update would help, does this open into a small foyer Railing, windows painted, I prefer black for this, I have attached a photo of a house that the owners had the roof painted, they painted all the metal windows themselves, said it was easy. Paving in front of entrance, this photo shows they used white pebbles and pavers with a small screen, plus a new hedge. similar entrance doors to these let in much needed light as these houses can be quite dark

Try monument

Hard to see the brick clearly on your photo, but it looks like plain colour brick without different colours through it, and no textured finish. So in this example you have a completely different coloured stone and a non patterned brick, which does look okay. But if your brick has various colours and you have a coloured stone wall then it is way too much and the texture and colours compete against each other. This is only my opinion.