Can't scroll up past heading after click takes you there

Hi,

I made this http://www.gingerling.co.uk/a-community-managers-notes-links-fosdem-2015/ – thanks so much for plugin it would be an impossible post with out it

One issue however, if you click a link on the index it takes you to the link but makes that heading the top of the page, and you can’t scroll back up again etc. This seems a bit odd, is it a bug?

(Also, the toggle index buttons don’t appear for me)

https://wordpress.org/plugins/table-of-contents-plus/