FWiW Australia used a CDC Cyber 205 for occassional weather modelling and other mathematical work in the early 1980s.

( There was a seperate dedicated weather computer, this one was used for 'other' jobs like speculative weather modelling, monster group algebraic fun, et al.)

https://en.wikipedia.org/wiki/CDC_Cyber

The UK was the first customer:

    In 1980, the successor to the Cyber 203, the Cyber 205 was announced. The UK Meteorological Office at Bracknell, England was the first customer and they received their Cyber 205 in 1981.

I thought the ECMWF models were (and always have been) global?

Only centred on Europe.

> European Centre for Medium-Range Weather Forecasts