HSE have no jurisdiction over (or practical interest in) accidents that happen outside UK - other than some categories that link to major hazards legislation. So absolutely no point in reporting it to them. However Australian legislation is similar and so someone responsible for the workplace there should have reported it to the relevant State or Commonwealth regulator. Obviously it should be reported and suitably investigated internally, and included in your internal statistics.

http://www.commerce.wa.g...eport-injury-and-disease Link to guidance for Western Australia, but sure it will be very similar across the country.