Irn Bru or Iron Brew?

So what is the difference between Irn Bru and Iron Brew, apart from the fact that one of them was three times the price of the other?

And does it contain iron? and if it does is it actually good for you?

And for the record... I didn't spend the whole of my day off lurking around discount supermarkets taking photos of the merchandise.
I also bought some food, made a pasta bake for the kids to heat up later, cleaned the bathroom, did some gardening, listened to switched off the budget, got a bath, went to a school governors' meeting, sent my novel off to the publishers and got a tattoo of George Osbourne on my bum.

Well, actually, a couple of the things in the list are not strictly true. I am just checking to see if anyone is still reading :-)