According to https://canarywharf.com/faqs/ the toilets here should be "behind James Shoe Care" but OSM has that mapped only in two *other* places on Canary Wharf: https://www.openstreetmap.org/node/3835357175/ in Cabot Square and https://www.openstreetmap.org/node/10218158153/ in Jubilee Walk. Suggest all three places be visited to check for current situation.