Michelle...there's a great behaviour management programme called 123 magic that is brillant for limit setting...and helping parents to be consistent...

It's designed for kids aged between 2-12 and works really well for mild to pretty severe behaviour problems.

I've used it for about 10 years in my work (I work in child and adolescent mental health) and just love it as it's about reducing the emotion and over-talk in behaviour management...once the kids get use to it, they respond to it really well...

It's also flexible...and is well aware of the tricky circumstances that things like shopping centres throw up to parents...

There's a guy in Perth who runs courses on it...PM me if you want the details...otherwise you get just get the book...the author is Thomas Phelan...

It won't just help with the situation you are talking about...but any parenting dilemmas...

Good luck!