I think there will be plenty for them to try. Boma is great because as a buffet, you can sample whatever you want and if you don't like it, leave it and go back and try something else. You should encourage your kids to give something a try if they are unsure - its a great, no risk way to expand one's food horizons. But if they strike out with the new stuff they try - there is a kids' section with the standard favorites, chicken fingers, etc.
Raglan road will be fine too. The creative names of the dishes on the menu make them sound more exotic than (most of) the dishes really are. If any of your kids are unsure, the fish and chips should be a sure winner, at least.