NewmodelATC
Yes the problem was probably too soon for the computers and displays at the time, but the success was due to the controllers having an input - I had the veto, but never used.
I will be away for a few days in Libya, but when I get back, I'll have a play with your concept. Funny to ask whether there was a possibility for a solution in Africa - I'll come back to that as I hope to be involved there.