as for AAT...
You can apply to become an AAT full member after completing the AAT Professional Diploma in Accounting.
Achieve AAT Accountant status
When you successfully complete the Professional Diploma in Accounting and meet our work experience requirement of 3 years, you can apply for AAT full membership and become a professional AAT Accountant (MAAT).
however AAT limits you to being either a book-keeper or an accountant.. however is a stepping stone to becoming a CA as you can join acca after that ... and having already done 3 years work experience will help propel you in ACCA to becoming a charted accountant much faster