Testers in USA and UK have tested a bunch of Manuka honeys for sale in those countries, and every one that did not come from New Zealand failed the test.
www.foodnavigator.com

Mānuka honey claims dismissed in UK and US: ‘All non-NZ brands failed the test’
Testing of non-New Zealand mānuka honey brands sold in the UK and US reveals all missed key indicators of mānuka according to New Zealand export standards.