Here is an e-mail from the original convenor and in effect the founder of the World Universities Debating Championships
On TAUSA and Honeywell - these were ad hoc competitions - from memory, TAUSA had no Australian/NZ (or Irish??) teams involved while Honeywell had no Irish, NZ or Canadian. Both were invitation competitions whereas the First Worlds set out to be (a) more open and (b) cover all of the world (or at least, initially, both North Americans, both ANZ and all four British Isles and the Caribbean).There are more details in the Minute Books of the GUU debates committee.
Ironically, my first idea for Worlds had been a TAUSA-like competition with the top 3 teams from each region who would have arisen out of local competitions and then 'Mace-like' be flown-to the Union to have the final rounds - but in 1981 in a UK recession, there was no sponsorship at all - so I made the competition into an open tournament. Thankfully!
Convenor of Debates, GU Union 1980 -81 and 1981,
Convenor, First World Debating Competition, 1981,
Observer Mace, 1982,
E-SU Tour, 1981.