The next morning we set off through a swing bridge and along the river, passing a novice driver, we reached the lock first. I got off to work the lock. A group of people were hanging around the gates and to reach it I had to say excuse me and as I squeezed past they laughed quietly as though embarrassed and slightly moved aside. There was some lighting and sharing of a metal pipe but my knowledge of drug taking is incomplete as to what was really going on. When I found it was not a push button lock like the others I had done I had to excuse myself again to go and get a windlass. The group let me past then skulked away, since I had disturbed their secluded recreation.