The UK Gov't has its own scientific advisors like Sir Patrick Vallance and he was hardly supportive of quarantine, so they won't pay much attention to what South East Asia and Australia think. You can't have quarantine for tourists but not for business travellers as the virus does not discriminate. British Airways said that there was no consultation and no scientific evidence provided to support the policy; that weekly commuters from France or Germany (ie Prof. Teo Yik-Ying comment about green lane arrangements) can be exempted. That was an economic decision and not a health decision..