what is the difference between a graduate diploma and a postgraduate diploma
Graduate diploma In the US, graduate diplomas are "Intermediate Graduate Qualifications" involving study beyond master's level but not reaching PhD level. They are generally found in professional, rather than academic, fields. Other qualifications at this level include advanced graduate certificates, specialist certificates and specialist degrees.[19]
Education in England At age 16 the students typically take exams for the General Certificate of Secondary Education (GCSE) or other Level 1/2 qualifications. While education is compulsory until 18, schooling is compulsory to 16, thus post-16 education can take a number of forms, and may be academic or vocational. This can involve continued schooling, known as "sixth form" or "college", leading (typically after two years of further study) to A-level qualifications (similar to a high school diploma in some other countries), or a number of alternative Level 3 qualifications such as Business and Technology Education Council (BTEC), the International Baccalaureate (IB), Cambridge Pre-U, WJEC or Eduqas. It can also include work-based apprenticeships or traineeships, or volunteering.[12][13]