Marjorie taught English in secondary schools forover 20 years, spending 9 years as a Head of Department in Port Talbot and working concurrently for WJEC as an examiner and moderator for GCSE English. In 1991, she moved to be the English Field Officer at the Curriculum Council for Wales, supoprting action research projects across Wales as part of the Teacher Support Programme, a post that was limited to 2 years but which gave her opportunities and contacts in schools across the country. She subsequently became an independent education consultant and trainer, working on a regular basis as English Adviser for Powys LA and also contributing to the advisory services of several other local authorities including Carmarthenshire and Cardiff. She also worked as an Estyn inspector for 10 years carrying out inspections of primary and secondary schools in England and Wales as a member of the core team.
In 2000, Marjorie became the English Subject Officer for English at ACCAC - later the Welsh Government - being part of the curriculum development team that produced the 2008 National Curriculum Order for English in Wales and of the regulatory team that accredited and scrutinised GCSE and A level examinations in English. She was also part of the team that produced the Skills framework and a trainer and mentor for the Developing Thinking and Assessment for Learning programme, delivering INSET and in-school support for teachers. Marjorie wrote many significant documents for ACCAC/WG, most recently the Guidance on the teaching of higher-order reading skills and Guidance on the teaching of writing.