I have found out that the Wordpress instructions are not right for everyone, as iframes will only work when you are on the business plan. If you have a free or premium plan you will be able to see it in the html preview, but it won't show up in the blog preview or when you publish it.
To get around this I've taken a screenshot of the tree then added a link to the tree at the bottom. Not as good as been able to have all the links live. If there are any techos out there that can find another solution that would be great.