From what I can understand of that post, you already called yesterday to add the sports boost. That is now active and that was used as your free boost. After that, if you want to continue with this you can then pay for it.
Sky Movies boost is not an option for the free upgrade as far as I am aware. The offer is for picturebox movies for 3 months.
There is a problem with the upgrade page which says I have added anytime calls even though I haven't. And just like you I am on a plus package.
Regardless, even when the website is put right, you have already made your choice in the way of the sports boost. It will automatically cancel at the end of the free period, and you can then choose to add it on again but pay for it in future. If you want any movies adding on, this will be chargeable for you to add now.