The Government of the United Kingdom of Great Britain and Northern Ireland and the Government of Australia,
Desiring to provide, on the basis of reciprocity, for the recognition and enforcement of judgments in civil and commercial matters;
Have agreed as follows:
www.opsi.gov.uk/SI/si1994/Uksi_19941901_en_2.htm
The above link basically says that a court order (Civil and Commercial Matters) made in either country, can be enforced in the other country. But Civil and Commerical matters are not consumer debt, ie credit cards etc