If the brick is a functioning chimney I would leave it other wise a rough render could work. One of the issues is that the nearby features such as the light and painting clash. As in the dining room, try a large mirror and a big photo e.g. to link it all. Also good rugs with strong reds, browns, oranges would help co-ordinate the rooms at low expense. I would try a colourful Moroccon style rug near the brick feature before attempting a major fix.

Firstly to replace a timber window with aluminium isn't necessarily a good move. The existing windows are probably around 40+ years old so have done a great job so far. While maintenance is required by oiling and/or painting they still have lasted quite well. 40+ is a long time exposed to the elements. Timber performs thermally much better than an aluminium frame. Even the modern thermally broken frames are probably only line ball at best with timber. Repainting a timber window is easier than changing colour on an aluminium one. So far changing to aluminium there is not really any obvious advantage...... The advantage with standard aluminium is really only the cost to purchase, yet a thermally broken is quite expensive...... I regularly change aluminium windows back to timber on many renovations due to the poor quality of the older aluminium frames and timber looks so darn good. Use timber windows with a high quality glass such as Low E, Laminated or double glazing. This will suit the house and perform a lot better. I personally like the existing frame and configurations so would probably only upgrade the glass with a high performance version.

Sorry this is so basic. I tried paint the house on the Dulux app but it didn't paint the "quoins" so I did some cut'n'paste using MS Paint. That is probably obvious, lol. It looks fairly patchy. I had to leave the paint work by the door. I would have like to have added awnings over windows but I'm not that clever! I think the window sill tiles would originally been black so I did dark trim as I was curious as to how it would look. You could probably use an online visualiser to get a better idea. If this were my home, I'd go straight to painting, no rendering, then get garden established.

Unless you have the money to update everything else to better complement the bricks, painting them will give you a much more updated look. Over the past 18mths I’ve been working on the front and landscape of my current house, including painting the bricks and it has made the world of difference! I’ve attached a before and after photo! Good luck.