Clau2000 our manufacturer was in Melbourne, supplier in Canberra. Despite being happy with the product we really struggled with the level of service from the supplier. Quite frankly the business owner was rude, uncommunicative and very difficult to deal with and I would hesitate to recommend her business to anyone. At one point we contacted the manufacturer but he insisted we had to go through his ACT supplier and could not order directly from him (either us or our builder). Our first set of windows were installed on a westerly facing wall & get direct sunlight for the hottest part of the summer afternoon, they have been installed for 4 years and are showing no sign of deterioration. We went with E10 glass, double glazed and they do an amazing job of blocking the summer heat.

Snap Sirius!! I just came from a meeting with a colour consultant at an inspiration store, lol! The consultant loves the choices as is. She liked Whisper White for the window frames and said the Surfmist windows on upper extension will be harmonious with them. She suggested Woodland Grey for rear extension roof was modern and felt leaving the tile on the original home was fun. She suggested Gully for the outer frame of window and baseboards, Woodland Grey for gutters with Whisper white for the Fascia. Gully for garage and base extension render with timber windows she liked too. So I guess, sorted? She thought a blue, teal or orange toned front door with the wire door sprayed in Woodland grey. She thought my gold ceiling room facing south could go with Hogs Bristle well, I might do that half strength though...

It's going to depend on personal taste a lot, but I like black windows with the brick, but maybe you're not planning on keeping the brick... I like the look below.

Lovely original home, good solar orientation on the extension. In my first impression the windows on the very left of the extension - the long upright rectangles - look out of place in the overall elevation. They are too similar to the windows on the original house immediately to the left, yet they are too different to the original windows, and present a jarring feeling. I would suggest either making them the same - ie double-hung of the same width and size as the original house on that elevation, or make them substantially different,like the windows in the extension in the rest of that elevation - eg one longer horizontal window near the ceiling. good luck!