And then of course orthodontic topics, the usual suspects like:

• Tooth movement
• Appliances (QH, RME, HG, URA, TWB, MOA)
• Retainers
• Orthodontic Materials (Archwires, brackets, adhesives..)
• Dental Materials (Alginate, GIC, SEP..)
• Diagnosis and treatment planning........etc.
• Technological advances (clear aligners and lingual appliances)

Now..

you already studied these topics for the viva or other components of the MOrth, you can find some relevant study materials in Bristol notes and other textbooks. Additionally, you should read any UK guidelines on these topics.