Just a thought... when you say 5 minutes out, I assume you mean if they break the rules they are out for 5 minutes? Have you thought about upping that each time? Say 5 the first time, then 10 then 15 - then out for good? Just wondering, maybe 5 minutes isn't enough to make a difference to them.

Absolutely the best thing ever to be consistent. Do whatever you have to, to put something in place that you can follow through. For us it was simplifying the rules, lessening the consequences (so that we can stick to it!) and following through every time.
Good luck, I know it can be hard.