Yeah the TC (stands for Twin Carb) was only available in NZ in 1971 and 1972, it featured a full black interior with those seats. In 1973 the TC was replaced with the Avenger Alpine which was a 1500 Twin Carb similar to the UK GLS, it 1974 the went to 1600 Twin Carb.
The engine from my 1975 Hillman Avenger is a 1500 from a 1973 Avenger Alpine.