Hazzle

Hi everyone We have a small mid-terraced property that we need to make more wheelchair friendly. Amongst other things, we were hoping to enlarge the existing small porch at the front, right across the front, to provide storage for an outdoor wheelchair. It would enclose the front door and the lounge window. But I think I read somewhere that buildings regs does not permit the only window to a room being enclosed in a porch. Am I right? And if so, why does a conservatory not fall under this rule? Many thanksporch-planning .pdf