The Major Things To Consider Before Starting An Extension

Hi great video. I was wondering if you could steer me in the right direction. I am planning on purchasing a habitable annex for my garden (with sleeping accommodation). The annex will be built from timber and be located 1m from all boundaries and around 7 meters from the main dwelling. I can’t seem to understand if timber construction will be okay given its 1m away from boundary? I came across a section on google and it said if it’s less than 1 meter it needs to be non combustible material. As this will be more than 1m away would timber be okay. Wanted to ask before I applied for planning and seek for a building regs application. Many thanks