Captain Dart. There was nothing wrong with the way the bases were set up before "onshoring". We work for a HK company and, in common with airlines and shipping companies around the World we can be expected to have bases in a variety of locations.
In the case of the UK, HMRC did a tax grab and made demands that cut across international conventions, namely that we be forced "onshore". CPA should have told HKIRD what was planned, but they didn't. Had they done so HKIRD would have reminded them that CPA are a company incorporated in HK and whose effective management is in HK and that the aircrew are still, in every respect, employed in HK. This could then have been used to stop HMRC in their tracks.
For reasons that few of us understand the previous GMA, who has scuttled off to Canada, acquiesced to the demands of HMRC without consulting HKIRD and allowed the current mess where we are caught between two governments. The international conventions are set up to avoid this eventuality, but don't ask the incompetents at HMRC to observe international conventions. They don't even seem to understand them.
You only work in the tax office when no other employer will take you. It is a form of welfare.