URGENT UPDATE
Rest Easy - seems there is ZERO Tax Risk.
In a Webinar this afternoon, a very active Tax Advisor very clearly stated that, for individuals (Not Traders/Business operators), any Capital Gains on gold bullion sales are NOT assessible for Income Tax. Additionally, in the case of inheritance, the Estate would have no tax liability and that recipients would only be subject to Tax if the Tax-Free inheritance threshold was exceeded eg. 100 million baht per recipient.
Very happy now about where this matter has finished - just disappointed about the confusion in reaching this conclusion.