Many terraced houses have a side return that's usually used for garden storage - but could be used to widen what is traditionally a long narrow back room. Here, the extension size is minimal, but the impact on the house is big, So, it's an inspiration in creating a modern home design with contemporary extension exterior.
When you plan your new extension, plan the garden at the same time - and get the work done as one job, if you can. For example, buy a flooring material for inside and out that matches (this helps stretch the space further visually), and plant around the extension. This will increase privacy and improve the view from indoors.