We're currently having an extension on our house - single storey to the back, and double to the side. It's a 1970s semi house, with green exterior tiles. Looks a bit like this:
media.rightmove.co.uk/4k/3899/40197467/3899_10002287A_2287_IMG_01_0000.JPG
We currently have white PVC windows and doors. At the front, I figured would stick with white windows but we might go with a pale green front door this time, but I've no idea what to do at the back. White bifolds might look a bit stark from outside, but would grey bifolds look silly with the green tiles? There will be a bit of separation between tiles and bifolds as there is the roof of the extension inbetween which will be grey.