So it seems that SE left her flat, which is located either on or very close to Brixton Hill, she walked down Brixton Hill and went into the Sainsburys Local located at 266-270 Brixton Hill to buy a bottle of wine. She then joined the A205 at the intersection at the bottom of Brixton Hill and walked along this road all the way to Clapham, including Poynders Rd, Cavendish Rd and through Clapham Common. So it’s likely this would of been the same way she was walking back and that she was staying on the main roads for her entire journey. The Mail said her boyfriend lives 2 minutes away from Poynders Rd in Clapham. So maybe she was planning to head home but spoke to him on the phone and they arranged to meet at his place as she was walking past anyway. She could have taken a road off of Poynders Rd heading in a new direction, towards her boyfriend’s place, and something has taken place on this road meaning that she never arrived.