An interesting question!
Under the ANO the CAA must grant a BCAR licence when satisfied that
a) the applicant is a fit person to hold the licence &
b) qualified by having the knowledge, experience, competence and skill etc
Whereas under Part 66 there is no fitness test as such. The Competent Authority shall issue the licence when satisfied that the applicant meets the standards of knowledge and experience etc.
Under Part 66 there is a list of items that could result in the licence being revoked, suspended or limited. the Competent Authority is required to determine the seriousness of the violation and take appropriate action. Under the ANO the CAA could take a view that these items mean you are no longer fit to hold a BCAR licence and take action accordingly.
Any sanctions applied by the CAA can be subject of an appeal.
Could a licence be revoked for ever? Probably not but there may be a significant time before a further application can be made.