I had another look under the steering column for the heated windscreen timer - the gray one, see photo in post #9 above. I can't find it anywhere. There are blue, black, yellow, and gray relays (labeled for other functions), but after 20 minutes of searching with a flashlight and groping where I couldn't see, I'm still not finding it. Does the timer live somewhere else? I also can't find the relevant diagram in my copy of RAVE. I'm leaving the kick panel off for now in case someone can give me precise directions, in which case I'll go back out and have a look for it again.
There is a space for the heated windscreen timer in a gap behind the black relay, but there is no female end for it to plug into. There is clearly a second row of other relays closer to the firewall, but nowhere I can find that would receive the gray timer that I have.