Thanks Steven.
The drawing is far from perfect. Unfortunately I work in a small room and my camera tripod doesn't get up to eye height, so I had it sitting on a swivel chair for this photo, as far back as I could get it. Despite my best efforts, I couldn't seem to get a shot from exactly my viewpoint, making it hard to judge the accuracy of the drawing from the photo. Plus I'm all fingers and thumbs with a camera. I'll try to get a better shot on the next one.
I must also thank you for your posts here on sight-size drawing, they've been a big help. The Bargue book also has a good section on sight-size.
I think part of the difficulty in teaching yourself this stuff is that no matter how strict you are with yourself, your eye is necessarily less developed than a drawing master's eye would be. There's no one to say, "Have another look at that left eye..."
I console myself with the thought that the practice will be excellent eye training, whether I produce any decent drawings or not.
Despite the aforementioned difficulties, on this drawing the shadows on the base, and the shadow cast by the base, fairly scream at me. You can see that on the photo, bad as it is. I got a bit tired and rushed that part. I had a strong word with myself and threatened to throw myself out of my atelier if I don't do better next time