We practiced 'sit' and leash training, and had a huge romp in the leash-free over by Kew Gardens - about a dozen dogs with half as many owners. Walter took a jump at a random girl walking by - no clue what the trigger was, or the warning sign.
Tuesday night, I took the down to the water to play, and did some hard work with holding a sit; they did reasonably well. Walter will hold until Hannah moves (usually). Hannah will hold until the toy moves.