Now I'm not quite sure what a balance pipe is for, especially on a locomotive with, as far as I know, a single water tank, but it is worth noting that the dimples marking where it should fit on the saddletank casting are in the wrong place. All the drawings and photos I've seen of Canopus show the pipe curling tightly under the boiler just to the front of the tank filler cap. If, however, you look at the saddletank casting the dimples are positioned just to the rear of the filler cap.
Fortunately this is easy to fix by simply drilling holes into the casting in the right place and using a little filler to cover the old dimples (and the first hole I started to drill in the wrong place). Once the saddletank is glued to the boiler fitting the balance pipe (just a bit of 0.8mm wire formed around the handle of my modelling knife) is nice and easy.
Now if you remember I hate fitting handrail knobs to the saddletank. Having eventually got them right, I've had to do them again, as I've discovered that the saddletank casting appears to be slightly twisted. I glued it into position and checked that it looked level from the front (i.e. the bottom of both sides were level) and that the tank filler cap was in line with the chimney etc. It was only once the glue had set solid that I discovered that at the cab end it isn't so level, which of course meant that the handrails weren't level. I did try to break the glue to re-position the tank but it isn't coming off, so I've tweaked the handrail holes slightly to try and get them level back to front and at the same height on each side. They aren't perfect but for normal viewing they will be fine; it will only be a close up inspection from directly in front where you might notice a problem.