Which, having also been involved in designing circuits for many years, I felt mine did, factoring in my previously made statement that it was to be built dirt cheap and with parts that I had laying about on that Saturday afternoon. However, having now thought about it some more, and having reviewed some of the other suggestions and solutions that people have come up with, I don't think that I would have actually designed it any other way. I might have used a different chip from the 4000 series, but probably not.
4011s are cheap and reliable and having had my circuit in daily use for a few weeks now, it does exactly what it says on the tin. Furthermore, most of the component values are not critical, and because of its non-invasive nature and ability to reliably monitor a large range of load levels - I checked all of this most carefully after John expressed an interest in Wiki - ising it and repurposing it for other uses - I am quite satisfied that it does what it was designed to, and potentially much more.Arfa