If I create 2 adverts and assign them both to the same area of the site it only ever shows 1 or the other.

I'd like to be able to show an ad at the top of the sidebar and one at the bottom, is that possible?

That's not possible in the current version, only one ad will be displayed at a time, selected randomly. I think there is a 3rd-party plugin that will do what you describe, however I don't remember its name. You may wish to check our Marketplace.

I have something that you might be interested. Send me PM for more details. 🙂