Authorised representative appearance in GST proceedings limited by eligibility and explicit disqualification criteria. The section permits appearance by an authorised representative except where personal examination is required, lists authorised categories (relatives or regular employees; practicing advocates; chartered accountants, cost accountants or company secretaries holding a certificate of practice; certain retired commercial tax officers subject to a post retirement bar; and authorised GST practitioners), and prescribes disqualification grounds-dismissal from government service, conviction for related offences, misconduct findings, and insolvency-with corresponding State or Union Territory disqualifications applicable under this Act.