Not quite what you asked but hopefully it will help. My dd does a cooking club after school one day a week, the woman that runs it charges £7 per session and you book in for a block of 10 lessons. She provides all of the ingredients and the kids bring home what they have cooked along with the recipe. Perhaps you could contact local schools to see if they would be interested in offering this kind of thing to their students?
just ring up someone who provides adult cooking classes and ask them for advice. it's mostly the same, isn't it?
I've been amazed at how willing people are to help - ring up a childrens cookery organiser somewhere else in the country and ask for advice - people who have struggled themselves and received help are usually happy to pass knowledge on
I think that good social networking and word of mouth advertising are more beneficial than a franchise. When I took dd to classes I did a search on classes in my area, but had no clue about specific brands or names.
The lady we ended up going to we met at a local fete with a stall offering biscuit decorating, so she could corner the parents while the kids were busy. She has a strong presence (local radio, fb, stand at local events etc) and apart from the recipe cards, she could have done pretty much all of it without being part of a franchise.
My SIL has set up her own business doing much the same thing and gets customers via fb and school contacts etc. Once you do a few parties and people get to know you they will recommend you.
Not sure if this will help at all, but MNT Training do a fantastic Childrens Nutrition Course, which, once you have qualified, will give you a little more clout with your client base...? Something to hold over your competitors maybe?