You are viewing an unimputed dividend as a return of capital which is taxed as a result of ending up in the shareholders pocket (the first pocket). I understand and agree with that way of looking at things.
I think what you are saying here is that by subtracting the imputed part of the dividend from the total dividend and effectively ignoring the imputed bit, I am effectively saying that the imputed part of the dividend does not exist. Therefore I should not take tax out of a dividend that I am claiming was effectively never paid in the first place?
However, I do not have this interpretation of what happened. I am not saying that the unimputed part of the dividend was not paid. I am saying it was paid but it had no cash benefit to the shareholder. If fact quite the opposite. The paying of the what is in effect shareholder capital back created a tax bill, which I think you acknowledge in the first part of your post that I have quoted.
SNOOPY