I found re-attaching these antennae connectors the trickiest bit by far as they appear very delicate and seating them correctly was fiddly. In the end lighting them from the side with a small torch helped to check their position before gently pushing them down. The first one made a clicking sound as it connected, the other two went on silently. MBP wifi working perfectly now. I’m fairly sure that was at least £100 of labour had I taken it in for repair so thanks ifixit for saving me money and for the warm glow of accomplishment!