Hi Dave
Longtimenosee!
Read this
Amazon.co.uk: Becoming Vegan: The Complete Guide to Adopting a Healthy Plant-based Diet: Books: Brenda Davis,Vesanto Melina
Very precise, informative and packed full of advice.
Also will save you some bucks on what should be an area that needs to be understood by the participant, not just by the teacher! (No offence intended to any nutrionists!)